124 results on '"Hubert J Krenner"'
Search Results
2. Quantum Control of Optically Active Artificial Atoms With Surface Acoustic Waves
- Author
-
Michael Choquer, Matthias Weis, Emeline D. S. Nysten, Michelle Lienhart, PaweL Machnikowski, Daniel Wigger, Hubert J. Krenner, and Galan Moody
- Subjects
Quantum dots (QDs) ,quantum networking and communications ,surface acoustic waves (SAWs) ,Atomic physics. Constitution and properties of matter ,QC170-197 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Surface acoustic waves (SAWs) are a versatile tool for realizing coherent quantum interfaces between various solid-state qubits spanning microwave to optical frequencies. Through strain, electric, or magnetic fields associated with acoustic waves, qubit states can be controlled and measured with exquisite precision for applications in quantum information processing, memory, transduction, and sensing. In this review, we discuss progress toward quantum control using surface acoustic waves coupled to optically active artificial atoms, including semiconductor quantum dots (QDs), optically addressable solid-state spins, and quantum emitters in van der Waals materials. We outline the device, material, and theoretical considerations for realizing interactions with surface acoustic waves in the quantum regime, summarize the state of the art in coupling surface acoustic waves to artificial atoms, and provide insight into the current trends and trajectory of the field.
- Published
- 2022
- Full Text
- View/download PDF
3. Resonance-fluorescence spectral dynamics of an acoustically modulated quantum dot
- Author
-
Daniel Wigger, Matthias Weiß, Michelle Lienhart, Kai Müller, Jonathan J. Finley, Tilmann Kuhn, Hubert J. Krenner, and Paweł Machnikowski
- Subjects
Physics ,QC1-999 - Abstract
Quantum technologies that rely on photonic qubits require a precise controllability of their properties. For this purpose hybrid approaches are particularly attractive because they offer a large flexibility to address different aspects of the photonic degrees of freedom. When combining photonics with other quantum platforms like phonons, quantum transducers have to be realized that convert between the mechanical and optical domain. Here, we realize this interface between phonons in the form of surface acoustic waves (SAWs) and single photons, mediated by a single semiconductor quantum dot exciton. In this combined theoretical and experimental study, we show that the different sidebands exhibit characteristic blinking dynamics that can be controlled by detuning the laser from the exciton transition. By developing analytical approximations we gain a better understanding of the involved internal dynamics. Our specific SAW approach allows us to reach the ideal frequency range of around 1 GHz that enables simultaneous temporal and spectral phonon sideband resolution close to the combined fundamental time-bandwidth limit.
- Published
- 2021
- Full Text
- View/download PDF
4. Scalable and Transfer-Free Fabrication of MoS2/SiO2 Hybrid Nanophotonic Cavity Arrays with Quality Factors Exceeding 4000
- Author
-
Sebastian Hammer, H. Moritz Mangold, Ariana E. Nguyen, Dominic Martinez-Ta, Sahar Naghibi Alvillar, Ludwig Bartels, and Hubert J. Krenner
- Subjects
Medicine ,Science - Abstract
Abstract We report the fully-scalable fabrication of a large array of hybrid molybdenum disulfide (MoS2) - silicon dioxide (SiO2) one-dimensional, free-standing photonic-crystal cavities capable of enhancement of the MoS2 photoluminescence at the narrow cavity resonance. We demonstrate continuous tunability of the cavity resonance wavelength across the entire emission band of MoS2 simply by variation of the photonic crystal periodicity. Device fabrication started by substrate-scale growth of MoS2 using chemical vapor deposition (CVD) on non-birefringent thermal oxide on a silicon wafer; it was followed by lithographic fabrication of a photonic crystal nanocavity array on the same substrate at more than 50% yield of functional devices. Our cavities exhibit three dominant modes with measured linewidths less than 0.2 nm, corresponding to quality factors exceeding 4000. All experimental findings are found to be in excellent agreement with finite difference time domain (FDTD) simulations. CVD MoS2 provides scalable access to a direct band gap, inorganic, stable and efficient emitter material for on-chip photonics without the need for epitaxy and is at CMOS compatible processing parameters even for back-end-of-line integration; our findings suggest feasibility of cavity based line-narrowing in MoS2-based on-chip devices as it is required for instance for frequency-multiplexed operation in on-chip optical communication and sensing.
- Published
- 2017
- Full Text
- View/download PDF
5. Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with Lithium Niobate
- Author
-
Michelle Lienhart, Michael Choquer, Emeline Nysten, Matthias Weiss, Kai Mueller, Jonathan J. Finley, Galan Moody, and Hubert J Krenner
- Subjects
Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Acoustics and Ultrasonics ,FOS: Physical sciences ,Physics - Applied Physics ,Applied Physics (physics.app-ph) ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Quantum Physics (quant-ph) ,Physics - Optics ,Optics (physics.optics) - Abstract
We report on scalable heterointegration of superconducting electrodes and epitaxial semiconductor quantum dots on strong piezoelectric and optically nonlinear lithium niobate. The implemented processes combine the sputter-deposited thin film superconductor niobium nitride and III-V compound semiconductor membranes onto the host substrate. The superconducting thin film is employed as a zero-resistivity electrode material for a surface acoustic wave resonator with internal quality factors $Q \approx 17000$ representing a three-fold enhancement compared to identical devices with normal conducting electrodes. Superconducting operation of $\approx 400\,\mathrm{MHz}$ resonators is achieved to temperatures $T>7\,\mathrm{K}$ and electrical radio frequency powers $P_{\mathrm{rf}}>+9\,\mathrm{dBm}$. Heterogeneously integrated single quantum dots couple to the resonant phononic field of the surface acoustic wave resonator operated in the superconducting regime. Position and frequency selective coupling mediated by deformation potential coupling is validated using time-integrated and time-resolved optical spectroscopy. Furthermore, acoustoelectric charge state control is achieved in a modified device geometry harnessing large piezoelectric fields inside the resonator. The hybrid quantum dot - surface acoustic wave resonator can be scaled to higher operation frequencies and smaller mode volumes for quantum phase modulation and transduction between photons and phonons via the quantum dot. Finally, the employed materials allow for the realization of other types of optoelectronic devices, including superconducting single photon detectors and integrated photonic and phononic circuits., submitted manuscript
- Published
- 2023
- Full Text
- View/download PDF
6. Handy nanoquakes
- Author
-
Hubert J. Krenner and Christoph Westerhausen
- Subjects
Mechanics of Materials ,Mechanical Engineering ,ddc:530 ,General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2022
7. High-Dimensional Acousto-optoelectric Correlation Spectroscopy Reveals Coupled Carrier Dynamics in Polytypic Nanowires
- Author
-
Gregor Koblmüller, Daniel Rudolph, Hubert J. Krenner, and Maximilian M. Sonner
- Subjects
Materials science ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Surface acoustic wave ,Resolution (electron density) ,Nanowire ,FOS: Physical sciences ,General Physics and Astronomy ,Applied Physics (physics.app-ph) ,Physics - Applied Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Molecular physics ,Piezoelectricity ,Condensed Matter::Materials Science ,Semiconductor ,Dynamic light scattering ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Spectroscopy ,business ,Optics (physics.optics) ,Physics - Optics - Abstract
The authors combine acousto-optoelectric and multichannel photon correlation spectroscopy to probe spatiotemporal carrier dynamics induced by a piezoelectric surface acoustic wave (SAW). The technique is implemented by combining phase-locked optical microphotoluminescence spectroscopy and simultaneous three-channel time-resolved detection. From the recorded time-correlated single-photon-counting data, the time transients of individual channels and the second- and third-order correlation functions are obtained with subnanosecond resolution. The method is validated by probing the correlations of SAW-driven carrier dynamics between three decay channels of a single polytypic semiconductor nanowire on a conventional ${\mathrm{Li}\mathrm{Nb}\mathrm{O}}_{3}$ SAW delay line chip. The method can be readily applied to other types of nanosystems and probes SAW-regulated charge-state preparation in quantum dots, charge-transfer processes in van der Waals heterostructures, or other types of hybrid nanoarchitectures.
- Published
- 2021
8. Resonance-fluorescence spectral dynamics of an acoustically modulated quantum dot
- Author
-
Tilmann Kuhn, Jonathan J. Finley, Hubert J. Krenner, Paweł Machnikowski, Daniel Wigger, Matthias Weiß, Michelle Lienhart, and Kai Müller
- Subjects
Surface (mathematics) ,Physics ,Photon ,Condensed Matter - Mesoscale and Nanoscale Physics ,Dynamics (mechanics) ,FOS: Physical sciences ,Acoustic wave ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Resonance fluorescence ,Semiconductor quantum dots ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Atomic physics ,Computer Science::Databases ,Optics (physics.optics) ,Physics - Optics - Abstract
Quantum technologies that rely on photonic qubits require a precise controllability of their properties. For this purpose hybrid approaches are particularly attractive because they offer a large flexibility to address different aspects of the photonic degrees of freedom. When combining photonics with other quantum platforms like phonons, quantum transducers have to be realized that convert between the mechanical and optical domain. Here, we realize this interface between phonons in the form of surface acoustic waves (SAWs) and single photons, mediated by a single semiconductor quantum dot exciton. In this combined theoretical and experimental study, we show that the different sidebands exhibit characteristic blinking dynamics that can be controlled by detuning the laser from the exciton transition. By developing analytical approximations we gain a better understanding of the involved internal dynamics. Our specific SAW approach allows us to reach the ideal frequency range of around 1 GHz that enables simultaneous temporal and spectral phonon sideband resolution close to the combined fundamental time-bandwidth limit.
- Published
- 2021
9. Spins in Optically Active Quantum Dots: Concepts and Methods
- Author
-
Oliver Gywat, Hubert J. Krenner, Jesse Berezovsky and Oliver Gywat, Hubert J. Krenner, Jesse Berezovsky
- Published
- 2009
10. Breakdown of Corner States and Carrier Localization by Monolayer Fluctuations in Radial Nanowire Quantum Wells
- Author
-
Anna Sitek, Gerhard Abstreiter, Hubert J. Krenner, Daniel Ruhstorfer, Markus Döblinger, D. Rudolph, Lisa Janker, Maximilian M. Sonner, Jonathan J. Finley, Gregor Koblmüller, Andrei Manolescu, and Achim Wixforth
- Subjects
3D optical data storage ,Materials science ,Mechanical Engineering ,Surface acoustic wave ,Nanowire ,Bioengineering ,Heterojunction ,02 engineering and technology ,General Chemistry ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Molecular physics ,Monolayer ,ddc:530 ,General Materials Science ,Charge carrier ,0210 nano-technology ,Quantum well - Abstract
We report a comprehensive study of the impact of the structural properties in radial GaAs-Al0.3Ga0.7As nanowire-quantum well heterostructures on the optical recombination dynamics and electrical transport properties, emphasizing particularly the role of the commonly observed variations of the quantum well thickness at different facets. Typical thickness fluctuations of the radial quantum well observed by transmission electron microscopy lead to pronounced localization. Our optical data exhibit clear spectral shifts and a multipeak structure of the emission for such asymmetric ring structures resulting from spatially separated, yet interconnected quantum well systems. Charge carrier dynamics induced by a surface acoustic wave are resolved and prove efficient carrier exchange on native, subnanosecond time scales within the heterostructure. Experimental findings are corroborated by theoretical modeling, which unambiguously show that electrons and holes localize on facets where the quantum well is the thickes...
- Published
- 2019
11. Optomechanical wave mixing by a single quantum dot
- Author
-
Matthias Weiß, Daniel Wigger, Tilmann Kuhn, Jonathan J. Finley, Kai Müller, Hubert J. Krenner, Maximilian Nägele, and Paweł Machnikowski
- Subjects
Physics ,Photon ,Sideband ,business.industry ,Phonon ,Physics::Optics ,Acoustic wave ,Electromagnetic radiation ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Surface wave ,ddc:530 ,Radio frequency ,business ,Optomechanics - Abstract
Wave mixing is an archetypical phenomenon in bosonic systems. In optomechanics, the bidirectional conversion between electromagnetic waves or photons at optical frequencies and elastic waves or phonons at radio frequencies is building on precisely this fundamental principle. Surface acoustic waves (SAWs) provide a versatile interconnect on a chip and thus enable the optomechanical control of remote systems. Here we report on the coherent nonlinear three-wave mixing between the coherent fields of two radio frequency SAWs and optical laser photons via the dipole transition of a single quantum dot exciton. In the resolved sideband regime, we demonstrate fundamental acoustic analogues of sum and difference frequency generation between the two SAWs and employ phase matching to deterministically enhance or suppress individual sidebands. This transfer between the acoustic and optical domains is described by theory that fully takes into account direct and virtual multiphonon processes. Finally, we show that the precision of the wave mixing is limited by the frequency accuracy of modern radio frequency electronics.
- Published
- 2021
12. Ultrafast electron cycloids driven by the transverse spin of a surface acoustic wave
- Author
-
Daniel Rudolph, Maximilian M. Sonner, Zubin Jacob, Farhad Khosravi, Gregor Koblmüller, Lisa Janker, and Hubert J. Krenner
- Subjects
Physics::General Physics ,Lithium niobate ,Nanophotonics ,Physics::Optics ,02 engineering and technology ,Electron ,01 natural sciences ,Physics::Fluid Dynamics ,chemistry.chemical_compound ,symbols.namesake ,Optics ,0103 physical sciences ,ddc:530 ,Rayleigh scattering ,010306 general physics ,Quantum well ,Research Articles ,Spin-½ ,Physics ,Multidisciplinary ,business.industry ,Surface acoustic wave ,SciAdv r-articles ,Acoustic wave ,021001 nanoscience & nanotechnology ,Physics::History of Physics ,ddc ,chemistry ,Computer Science::Sound ,symbols ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,business ,Research Article - Abstract
Electron cycloids reveal the spin of a surface acoustic wave predicted by Lord Rayleigh in 1885., Spin-momentum locking is a universal wave phenomenon promising for applications in electronics and photonics. In acoustics, Lord Rayleigh showed that surface acoustic waves exhibit a characteristic elliptical particle motion strikingly similar to spin-momentum locking. Although these waves have become one of the few phononic technologies of industrial relevance, the observation of their transverse spin remained an open challenge. Here, we observe the full spin dynamics by detecting ultrafast electron cycloids driven by the gyrating electric field produced by a surface acoustic wave propagating on a slab of lithium niobate. A tubular quantum well wrapped around a nanowire serves as an ultrafast sensor tracking the full cyclic motion of electrons. Our acousto-optoelectrical approach opens previously unknown directions in the merged fields of nanoacoustics, nanophotonics, and nanoelectronics for future exploration.
- Published
- 2020
13. Photon scattering from a quantum acoustically modulated two-level system
- Author
-
Thilo Hahn, Daniel Groll, Hubert J. Krenner, Tilmann Kuhn, Paweł Machnikowski, and Daniel Wigger
- Subjects
Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Computer Networks and Communications ,FOS: Physical sciences ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Computational Theory and Mathematics ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Condensed Matter::Strongly Correlated Electrons ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Quantum Physics (quant-ph) - Abstract
We calculate the resonance fluorescence signal of a two-level system coupled to a quantized phonon mode. By treating the phonons in the independent boson model and not performing any approximations in their description, we also have access to the state evolution of the phonons. We confirm the validity of our model by simulating the limit of an initial quasi-classical coherent phonon state, which can be compared to experimentally confirmed results in the semiclassical limit. In addition we predict photon scattering spectra in the limit of purely quantum mechanical phonon states by approaching the phononic vacuum. Our method further allows us to simulate the impact of the light scattering process on the phonon state by calculating Wigner functions. We show that the phonon mode is brought into characteristic quantum states by the optical excitation process.
- Published
- 2022
14. Integrated quantum dot optomechanics
- Author
-
Xueyong Yuan, Anja Vogele, Saimon Filipe Covre da Silva, Benjamin Mayer, Armando Rastelli, Emeline D. S. Nysten, Matthias Weiß, Maximilian M. Sonner, and Hubert J. Krenner
- Subjects
Physics ,Quantum dot ,business.industry ,Optoelectronics ,business ,Optomechanics - Published
- 2020
15. The 2019 Surface Acoustic Waves Roadmap
- Author
-
P. Rovillain, Dirk Volkmer, Hubert J. Krenner, Andrew Cleland, Laura Thevenard, Christopher Bäuerle, Manuel S. Brugger, Jean Yves Duquesne, Tristan Meunier, Achim Wixforth, Alexander Reiner, Hailin Wang, Jonathan M. Cooper, E. A. Cerda-Méndez, Martin Wiklund, Gerhard Fischerauer, Florian Rehfeldt, Dmytro Denysenko, Yong Qing Fu, Emeline D.S. Nysten, Christoph Westerhausen, M. J. A. Schuetz, Max Marangolo, Marcelo Wu, Per Delsing, C. J. B. Ford, Henrik Bruus, Catherine Gourdon, Julien Reboud, Werner Dipl Phys Ruile, Geza Giedke, Kartik Srinivasan, Johannes Knörzer, J. Ignacio Cirac, Matthias Weiß, Krishna C. Balram, Ben Paschke, Paulo V. Santos, Geoff R. Nash, Chalmers University of Technology [Göteborg], University of Chicago, Harvard University [Cambridge], Max-Planck-Institut für Quantenoptik (MPQ), Max-Planck-Gesellschaft, Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), National Institute of Standards and Technology [Gaithersburg] (NIST), Circuits électroniques quantiques Alpes (QuantECA ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Cavendish Laboratory, University of Cambridge [UK] (CAM), Paul-Drude-Institut für Festkörperelektronik (PDI), Universidad Autonoma de San Luis Potosi [México] (UASLP), University of Oregon [Eugene], University of Augsburg [Augsburg], University of Exeter, Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Photons, Magnons et Technologies Quantiques (INSP-E11), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Acoustique pour les nanosciences (INSP-E3), Croissance et propriétés de systèmes hybrides en couches minces (INSP-E8), Universität Bayreuth, Technical University of Denmark [Lyngby] (DTU), Royal Institute of Technology [Stockholm] (KTH ), University of Glasgow, University of Northumbria at Newcastle [United Kingdom], University of Göttingen, University of Göttigen, Knörzer, J [0000-0002-7318-3018], Giedke, G [0000-0002-9676-5686], Cirac, JI [0000-0003-3359-1743], Baüerle, C [0000-0001-7393-0346], Ford, CJB [0000-0002-4557-3721], Santos, PV [0000-0002-0218-8030], Cerda-Méndez, E [0000-0002-6479-6664], Wang, H [0000-0001-7614-2003], Krenner, HJ [0000-0002-0696-456X], Nash, GR [0000-0002-5321-4163], Thevenard, L [0000-0002-4723-2955], Gourdon, C [0000-0001-9901-1399], Marangolo, M [0000-0001-6211-8168], Duquesne, JY [0000-0001-9156-8758], Fischerauer, G [0000-0003-2000-4730], Reboud, J [0000-0002-6879-8405], Cooper, JM [0000-0002-2358-1050], Fu, YQ [0000-0001-9797-4036], Rehfeldt, F [0000-0001-9086-3835], Westerhausen, C [0000-0001-7103-7060], and Apollo - University of Cambridge Repository
- Subjects
Acoustics and Ultrasonics ,Computer science ,H600 ,Microfluidics ,quantum acoustics ,02 engineering and technology ,phononics ,01 natural sciences ,QETLabs ,0103 physical sciences ,Wireless ,ddc:530 ,010306 general physics ,Quantum ,ComputingMilieux_MISCELLANEOUS ,business.industry ,Surface acoustic wave ,Ranging ,Acoustic wave ,surface acoustic waves ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Engineering physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Radio frequency ,0210 nano-technology ,business ,Quantum acoustics - Abstract
Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.
- Published
- 2019
16. Integration of Single Quantum Dots in Suspended Phononic Waveguides
- Author
-
Matthias Weiß, Hubert J. Krenner, Xueyong Yuan, Saimon Filipe Covre da Silva, Maximilian M. Sonner, Armando Rastelli, Emeline D. S. Nysten, and Anja Vogele
- Subjects
Materials science ,business.industry ,Physics::Optics ,Heterojunction ,Acoustic wave ,law.invention ,symbols.namesake ,law ,Quantum dot ,Excited state ,symbols ,Optoelectronics ,Phase velocity ,Rayleigh scattering ,business ,Waveguide ,Common emitter - Abstract
In fundamental research, surface acoustic waves (SAWs), nanoscale earthquakes on a chip are an extremely versatile tool to dynamically probe and manipulate charge and spin excitations condensed matter systems. When excited on piezoelectric materials both the oscillating mechanical stress of the SAW and its accompanying electric fields can be harnessed to establish strong interactions between single quantum emitters and sound on the nanoscale [1–4]. Here, we report on the integration of single quantum emitters in suspended phononic waveguides. Figure 1 (a) shows an electron micrograph of a 50 μm long and 2 μm wide suspended beam patterned on an approximately 150 nm thick (Al)GaAs heterostructure containing a single layer of GaAs quantum dots (QDs). In our experiment a Rayleigh SAW is excited by a multiharmonic frequency-chirped transducer [5] excited on the unpatterned region and coupled into the suspended beam where it propagates as a Lamb mode of identical frequency [6]. Figure 1 (b) and (c) compare the optomechanical response of a single QD in the unpatterend region and in the suspended beam, respectively. Clearly, the optomechanical of the quantum emitter inside the suspended phononic waveguide is enhanced by a factor of 3.5, compared to that of the emitter strained by the Rayleigh SAW. This finding may arise from an enhancement of the optomechanical coupling between the emitter and the elastic wave in the one-dimensional phononic waveguide. Employing phase resolved spectroscopy on an ensemble of quantum emitters we can unambiguously show, that the observed optomechanical response arises from the coupling between the low phase velocity, anti-symmetric (flexural) Lamb-Mode and the QD. Moreover, our fabricated phononic waveguides exhibit low propagation losses.
- Published
- 2019
17. Quantum dot optomechanics in suspended nanophononic strings
- Author
-
Benjamin Mayer, Saimon Filipe Covre da Silva, Armando Rastelli, Xueyong Yuan, Maximilian M. Sonner, Anja Vogele, Hubert J. Krenner, Emeline D. S. Nysten, and Matthias Weiß
- Subjects
Nuclear and High Energy Physics ,Physics::Optics ,FOS: Physical sciences ,02 engineering and technology ,Applied Physics (physics.app-ph) ,01 natural sciences ,Molecular physics ,String (physics) ,symbols.namesake ,Lamb waves ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Electrical and Electronic Engineering ,Rayleigh scattering ,010306 general physics ,Mathematical Physics ,Optomechanics ,Physics ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Surface acoustic wave ,Statistical and Nonlinear Physics ,Acoustic wave ,Physics - Applied Physics ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Computational Theory and Mathematics ,Quantum dot ,symbols ,0210 nano-technology ,Mechanical wave ,Quantum Physics (quant-ph) ,Physics - Optics ,Optics (physics.optics) - Abstract
The optomechanical coupling of quantum dots and flexural mechanical modes is studied in suspended nanophononic strings. The investigated devices are designed and monolithically fabricated on an (Al)GaAs heterostructure. Radio frequency elastic waves with frequencies ranging between $f$=250 MHz to 400 MHz are generated as Rayleigh surface acoustic waves on the unpatterned substrate and injected as Lamb waves in the nanophononic string. Quantum dots inside the nanophononic string exhibit a 15-fold enhanced optomechanical modulation compared to those dynamically strained by the Rayleigh surface acoustic wave. Detailed finite element simulations of the phononic mode spectrum of the nanophononic string confirm, that the observed modulation arises from valence band deformation potential coupling via shear strain. The corresponding optomechanical coupling parameter is quantified to $0.15 \mathrm{meV nm^{-1}}$. This value exceeds that reported for vibrating nanorods by approximately one order of magnitude at 100 times higher frequencies. Using this value, a derive vertical displacements in the range of 10 nm is deduced from the experimentally observed modulation. The results represent an important step towards the creation of large scale optomechanical circuits interfacing single optically active quantum dots with optical and mechanical waves., Comment: Submitted manuscript
- Published
- 2019
- Full Text
- View/download PDF
18. Surface acoustic wave-driven carrier dynamics as a contact-less probe for mobilities of photogenerated carriers in undoped nanowires
- Author
-
Daniel Rudolph, Jonathan J. Finley, Florian J. R. Schülein, Hubert J. Krenner, Jörg B. Kinzel, Achim Wixforth, Gerhard Ab Streiter, Gregor Koblmüller, and Matthias Weiss
- Subjects
Electron mobility ,Materials science ,Photoluminescence ,business.industry ,Surface acoustic wave ,Phase (waves) ,Nanowire ,Optoelectronics ,Charge carrier ,ddc:530 ,Electron ,business ,Excitation - Abstract
This paper presents a surface acoustic wave (SAW) technique that provides a contact-less and massively parallel probe for the intrinsic mobilities of electrons and holes in otherwise undoped surface-passivated GaAs/AlGaAs core-shell NWs. To resolve the SAW-driven carrier dynamics, stroboscopic time-correlated single photon counting (s-TCSPC) of the photoluminescence (PL) emission of individual NWs was performed. When subject to a SAW (fSAW = 194 MHz, PSAW = +5 dBm), a characteristic beating in the PL transient (blue), matching TSAW = 5.1 ns is observed. As expected, this beating shifts in time by TSAW/2 as the local acoustic phase is tuned by 180° (green). This observation is a direct fingerprint of the charge carrier dynamics and acoustic charge conveyance within the SAW-induced type-II band edge modulation. Electrons transfer from the position of the excitation laser (x0) into the energetically favourable stable points at the minimum of the conduction band. In contrast to electrons, holes remain stationary at the point of photogeneration due to their reduced mobility. TSAW/2 later these electrons are conveyed to the position of the holes giving rise to the observed beating.
- Published
- 2018
19. Active plasmonics with surface acoustic waves: dynamic electro-mechanical control over a surface plasmon polariton launcher
- Author
-
Hubert J. Krenner, Achim Wixforth, Frederike Förster, C. Ruppert, Artur Zrenner, Joerg B. Kinzel, and Markus Betz
- Subjects
Surface (mathematics) ,Materials science ,business.industry ,Physics::Optics ,Acoustic wave ,Grating ,Diffraction efficiency ,Surface plasmon polariton ,Optics ,Surface wave ,Physics::Accelerator Physics ,Optoelectronics ,business ,Surface deformation ,Plasmon - Abstract
500 MHz surface acoustic waves travel across a commensurate plasmonic grating coupler. A stroboscopic optical technique shows that the dynamic surface deformation deliberately modulates the coupler's efficiency by +/-2\% during the ~2ns acoustic cycle
- Published
- 2018
20. Optical Preparation of Stable Supercooled VO2 Nanocrystals: A Route Towards Reconfigurable Photonic Devices for TelecomWavelengths
- Author
-
Markus Betz, Helmut Karl, Thorben Jostmeier, Johannes Zimmer, and Hubert J. Krenner
- Subjects
Phase transition ,Materials science ,genetic structures ,business.industry ,Physics::Optics ,Nanotechnology ,Diffraction efficiency ,eye diseases ,Condensed Matter::Materials Science ,Hysteresis ,Wavelength ,Nanocrystal ,Thin film ,Photonics ,business ,Diffraction grating - Abstract
Single-domain VO2 nanocrystals in a fused silica matrix exhibit an extremely large thermally and/or optically induced hysteresis around room temperature. We demonstrate optical imprinting of persistent diffraction gratings and repetitive (> 104) cycling through the phase transition.
- Published
- 2018
21. Time domain investigation of radio frequency acousto-mechanical tuning of photonic crystal nanocavity modes
- Author
-
Hubert J. Krenner, D. A. Fuhrmann, Achim Wixforth, Dirk Bouwmeester, Hyochul Kim, Stephan Kapfinger, Pierre Petroff, and Susanna M. Thon
- Subjects
Materials science ,business.industry ,Cavity quantum electrodynamics ,Phase (waves) ,Nanophotonics ,Physics::Optics ,Acoustic wave ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Optics ,Computer Science::Sound ,Surface wave ,Optoelectronics ,ddc:530 ,Time domain ,Radio frequency ,business ,Photonic crystal - Abstract
Surface acoustic waves (SAWs) have proven a useful tool for dynamically manipulating the optical properties of semiconductor nanostructures. Recently we have shown that the mechanical deformation induced by a SAW on a two-dimensional photonic crystal membrane (PCM) spectrally tunes the resonance frequency of nanocavities within the PCM employing phase locked stroboscopic excitation.
- Published
- 2018
22. The Native Material Limit of Electron and Hole Mobilities in Semiconductor Nanowires
- Author
-
Florian J. R. Schülein, Lisa Janker, Matthias Weiß, Hubert J. Krenner, Dominik D. Bühler, Daniel Rudolph, Markus Döblinger, Gerhard Abstreiter, Jonathan J. Finley, Jörg B. Kinzel, Max Bichler, Achim Wixforth, Stefanie Morkötter, Michael Heigl, and Gregor Koblmüller
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,business.industry ,General Engineering ,Nanowire ,Shell (structure) ,General Physics and Astronomy ,02 engineering and technology ,Electron ,Acoustic wave ,021001 nanoscience & nanotechnology ,01 natural sciences ,Piezoelectricity ,Core (optical fiber) ,Semiconductor ,0103 physical sciences ,ddc:530 ,General Materials Science ,Charge carrier ,0210 nano-technology ,business - Abstract
Piezoelectric surface acoustic waves are employed to induce radio frequency spatiotemporal dynamics of photogenerated electrons and holes in the GaAs core of individual GaAs/AlGaAs core/shell semiconductor nanowires. Comparison of the time-dependent interband optical recombination to numerical simulations allow to determine the charge carrier transport mobilities of electrons, μe = 500–250+500 cm2/(V s), holes, μh = 50–30+50 cm2/(V s) and their ratio μe:μh = (20 ± 5):1. Our method probes carrier transport at low carrier density. Thus, the obtained values represent the native material limit of these nanowires, determined by their structural properties. We show that for near-pristine nanowires, individual twin defects do not significantly affect electrical transport, in strong contrast to polytypic nanowires. In the acoustoelectrically modulated emission, we observe unambiguous signatures of (i) hole localization within long wurtzite-rich segments and (ii) electrons in zinc blende regions being reflected at...
- Published
- 2016
23. A hybrid (Al)GaAs-LiNbO3surface acoustic wave resonator for cavity quantum dot optomechanics
- Author
-
Emeline D. S. Nysten, Armando Rastelli, and Hubert J. Krenner
- Subjects
Materials science ,Quantum decoherence ,Surface acoustic wave resonators ,Physics and Astronomy (miscellaneous) ,FOS: Physical sciences ,Applied Physics (physics.app-ph) ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,Resonator ,Quality (physics) ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,ddc:530 ,Optomechanics ,010302 applied physics ,Coupling ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Heterojunction ,Physics - Applied Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Quantum dot ,Optoelectronics ,0210 nano-technology ,business ,Optics (physics.optics) ,Physics - Optics - Abstract
A hybrid device comprising a (Al)GaAs quantum dot heterostructure and a LiNbO$_3$ surface acoustic wave resonator is fabricated by heterointegration. High acoustic quality factors $Q>4000$ are demonstrated for an operation frequency $f\approx 300$ MHz. The measured large quality factor-frequency products $Q\times f>10^{12}$ ensures the suppression of decoherence due to thermal noise for temperatures exceeding $T>50\,\mathrm{K}$. Frequency and position dependent optomechanical coupling of single quantum dots and the resonator modes is observed., Accepted manuscript
- Published
- 2020
24. A frequency-tunable nanomembrane mechanical oscillator with embedded quantum dots
- Author
-
Hubert J. Krenner, Oliver G. Schmidt, Michael Schwendtner, Yongheng Huo, Javier Martín-Sánchez, Armando Rastelli, Giovanni Piredda, Johannes Edlinger, Xueyong Yuan, Huiying Huang, Bernhard Jakoby, Christian G. Diskus, Rinaldo Trotta, Austrian Science Fund, Austrian National Bank, European Research Council, European Commission, China Scholarship Council, National Natural Science Foundation of China, Principado de Asturias, Xueyong, Yuan, Martín-Sánchez, Javier, Jakoby, Bernhard, Krenner, Hubert J., Rastelli, Armando, Xueyong, Yuan [0000-0001-6257-0154], Martín-Sánchez, Javier [0000-0002-6601-9447], Jakoby, Bernhard [0000-0002-2918-7150], Krenner, Hubert J. [0000-0002-0696-456X], and Rastelli, Armando [0000-0002-1343-4962]
- Subjects
010302 applied physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Physics and Astronomy (miscellaneous) ,European research ,media_common.quotation_subject ,FOS: Physical sciences ,Library science ,Physics - Applied Physics ,Applied Physics (physics.app-ph) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,Excellence ,Political science ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,media_common.cataloged_instance ,ddc:530 ,European union ,0210 nano-technology ,Excellence initiative ,media_common - Abstract
Hybrid systems consisting of a quantum emitter coupled to a mechanical oscillator are receiving increasing attention for fundamental science and potential applications in quantum technologies. In contrast to most of the presented works in this field, in which the oscillator eigenfrequencies are irreversibly determined by the fabrication process, we present here a simple approach to obtain frequency-tunable mechanical resonators based on suspended nanomembranes. The method relies on a micromachined piezoelectric actuator, which we use both to drive resonant oscillations of a suspended Ga(Al)As membrane with embedded quantum dots and to fine-tune their mechanical eigenfrequencies. Specifically, we excite oscillations with frequencies of at least 60 MHz by applying an AC voltage to the actuator and tune the eigenfrequencies by at least 25 times their linewidth by continuously varying the elastic stress state in the membranes through a DC voltage. The light emitted by optically excited quantum dots is used as a sensitive local strain gauge to monitor the oscillation frequency and amplitude. We expect that our method has the potential to be applicable to other optomechanical systems based on dielectric and semiconductor membranes possibly operating in the quantum regime., This work was supported by the FWF (P 29603), the Linz Institute of Technology (LIT), the LIT Secure and Correct Systems Lab funded by the state of Upper Austria, the EU project HANAS (No. 601126210), AWS Austria Wirtschaftsservice (PRIZE Programme, Grant No. P1308457), the European Research council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (SPQRel, Grant Agreement No. 679183), and the German Excellence Initiative via the Cluster of Excellence Nanosystems Initiative Munich (NIM). X. Yuan acknowledges support of the China Scholarship Council (CSC, No. 201306090010). Y. Huo thanks support of NSFC (No. 11774326) and STCSM (Nos. 17ZR1443900 and 17PJ1409900). J.M.-S. acknowledges support through the Clarín Programme from the Government of the Principality of Asturias and a Marie Curie-COFUND European grant (No. PA-18-ACB17-29).
- Published
- 2019
25. Recent progress on the scalable fabrication of hybrid polymer/SiO2 nanophotonic cavity arrays with an encapsulated MoS2 film
- Author
-
Ludwig Bartels, Dominic Martinez-Ta, Sebastian Hammer, Sahar Naghibi Alvillar, Hans-Moritz Mangold, Hubert J. Krenner, and Ariana E. Nguyen
- Subjects
chemistry.chemical_classification ,Materials science ,Fabrication ,chemistry ,Scalability ,Nanophotonics ,Nanotechnology ,Polymer - Published
- 2018
26. Multiharmonic Frequency-Chirped Transducers for Surface-Acoustic-Wave Optomechanics
- Author
-
Armando Rastelli, Achim Wixforth, Eugenio Zallo, Hubert J. Krenner, Oliver G. Schmidt, Paola Atkinson, Andreas L. Hörner, Matthias Weiß, Croissance et propriétés de systèmes hybrides en couches minces (INSP-E8), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, Universität Augsburg [Augsburg], Croissance et propriétés de systèmes hybrides en couches minces ( INSP-E8 ), Institut des Nanosciences de Paris ( INSP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), and Leibniz Institute for Solid State and Materials Research - IFW Dresden (Dresden, Germany)
- Subjects
General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Applied Physics (physics.app-ph) ,01 natural sciences ,Electromagnetic radiation ,Optics ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,010306 general physics ,Spectroscopy ,Optomechanics ,ComputingMilieux_MISCELLANEOUS ,Physics ,[PHYS]Physics [physics] ,[ PHYS ] Physics [physics] ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Surface acoustic wave ,Physics - Applied Physics ,Acoustic wave ,021001 nanoscience & nanotechnology ,Chip ,Transducer ,Quantum dot ,0210 nano-technology ,business ,Physics - Optics ,Optics (physics.optics) - Abstract
Wide passband interdigital transducers are employed to establish a stable phase-lock between a train of laser pulses emitted by a mode-locked laser and a surface acoustic wave generated electrically by the transducer. The transducer design is based on a multi-harmonic split-finger architecture for the excitation of a fundamental surface acoustic wave and a discrete number of its overtones. Simply by introducing a variation of the transducer's periodicity $p$, a frequency chirp is added. This combination results in wide frequency bands for each harmonic. The transducer's conversion efficiency from the electrical to the acoustic domain was characterized optomechanically using single quantum dots acting as nanoscale pressure sensors. The ability to generate surface acoustic waves over a wide band of frequencies enables advanced acousto-optic spectroscopy using mode-locked lasers with fixed repetition rate. Stable phase-locking between the electrically generated acoustic wave and the train of laser pulses was confirmed by performing stroboscopic spectroscopy on a single quantum dot at a frequency of 320 MHz. Finally, the dynamic spectral modulation of the quantum dot was directly monitored in the time domain combining stable phase-locked optical excitation and time-correlated single photon counting. The demonstrated scheme will be particularly useful for the experimental implementation of surface acoustic wave-driven quantum gates of optically addressable qubits or collective quantum states or for multi-component Fourier synthesis of tailored nanomechanical waveforms., Comment: revised manuscript
- Published
- 2018
27. Interfacing quantum emitters with propagating surface acoustic waves
- Author
-
Matthias Weiß and Hubert J. Krenner
- Subjects
Physics ,Photon ,Acoustics and Ultrasonics ,business.industry ,Nanowire ,02 engineering and technology ,Acoustic wave ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Resonator ,Semiconductor ,Quantum dot ,0103 physical sciences ,Optoelectronics ,ddc:530 ,010306 general physics ,0210 nano-technology ,business ,Quantum - Abstract
In this topical review, we report on recent advances on the coupling of single semiconductor quantum emitters, quantum dots, to the dynamic strain and electric fields of surface acoustic waves. Quantum dots are atom-like optically addressable two-level systems embedded in semiconductor matrices. On the one hand, the occupancy states of these 'artificial atoms' can be programmed by spatio-temporal carrier dynamics driven by sound waves. On the other hand, the quantized energy levels of electrons and holes couple strongly to the mechanical strain of these waves. We present an overview of the fundamental coupling mechanisms, experimental techniques to probe these systems in the time domain, and recent hallmark experiments. We discuss emerging research themes including hybrid architectures comprising advanced LiNbO3 SAW devices and single quantum dot devices of nanowire-based quantum emitters, and sound-driven control of light-matter interaction between single photons in nanophotonic resonators and two-level quantum dot systems.
- Published
- 2018
28. Scalable and Transfer-Free Fabrication of MoS2/SiO2 Hybrid Nanophotonic Cavity Arrays with Quality Factors Exceeding 4000
- Author
-
Dominic Martinez-Ta, Ludwig Bartels, Sahar Naghibi Alvillar, Sebastian Hammer, H. Moritz Mangold, Ariana E. Nguyen, and Hubert J. Krenner
- Subjects
Materials science ,Fabrication ,Science ,Nanophotonics ,FOS: Physical sciences ,Applied Physics (physics.app-ph) ,02 engineering and technology ,Substrate (electronics) ,Chemical vapor deposition ,01 natural sciences ,Article ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,Wafer ,010306 general physics ,Photonic crystal ,Condensed Matter - Materials Science ,Multidisciplinary ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Materials Science (cond-mat.mtrl-sci) ,Physics - Applied Physics ,021001 nanoscience & nanotechnology ,Optoelectronics ,Medicine ,Direct and indirect band gaps ,Photonics ,0210 nano-technology ,business ,Optics (physics.optics) ,Physics - Optics - Abstract
We report the fully-scalable fabrication of a large array of hybrid molybdenum disulfide (MoS$_2$) - silicon dioxide (SiO$_2$) one-dimensional, free-standing photonic-crystal cavities capable of enhancement of the MoS$_2$ photoluminescence at the narrow cavity resonance. We demonstrate continuous tunability of the cavity resonance wavelength across the entire emission band of MoS$_2$ simply by variation of the photonic crystal periodicity. Device fabrication started by substrate-scale growth of MoS$_2$ using chemical vapor deposition (CVD) on non-birefringent thermal oxide on a silicon wafer; it was followed by lithographic fabrication of a photon crystal nanocavity array on the same substrate at more than 50% yield of functional devices. Our cavities exhibit three dominant modes with measured linewidths less than 0.2 nm, corresponding to quality factors exceeding 4000. All experimental findings are found to be in excellent agreement with finite difference time domain simulations., accepted for Scientific Reports (2017)
- Published
- 2017
29. Large-area grown MoS2 and its integration in geometrically tunable photonic crystal cavities
- Author
-
Sebastian Hammer, H. M. Mangold, Dominic Martinez-Ta, Ariana E. Nguyen, Hubert J. Krenner, and Ludwig Bartels
- Subjects
Materials science ,business.industry ,Band gap ,Nanophotonics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Semiconductor ,0103 physical sciences ,Monolayer ,Optoelectronics ,Direct and indirect band gaps ,Photonics ,010306 general physics ,0210 nano-technology ,business ,Lasing threshold ,Photonic crystal - Abstract
Monolayer Transition Metal Dichalcogenides (TMDs) have recently attracted great interest in the field of photonics because of their distinctive optical and spin properties. In contrast to bulk TMD materials, which are indirect bandgap semiconductors, monolayer TMDs are highly optically active due to a direct bandgap ranging between 1 and 2 eV [1]. The coupling of TMD excitons to optical fields can be dramatically enhanced by integration with nanophotonic resonators. For instance, enhanced light extraction, signatures of Purcell enhanced emission and even lasing in coupled systems of TMD monolayers transferred onto two-dimensional GaP-based photonic crystal cavities (PCCs) [2,3] as well as microdisk cavities [4] was reported.
- Published
- 2017
30. Combined electrical transport and capacitance spectroscopy of a ${\mathrm{MoS_2-LiNbO_3}}$ field effect transistor
- Author
-
W. Michailow, Ludwig Bartels, B. Möller, Edwin Preciado, F. J. R. Schülein, G. v. Son, Achim Wixforth, John Mann, Hubert J. Krenner, Ariana E. Nguyen, and A. L. Hörner
- Subjects
Physics ,Free electron model ,Range (particle radiation) ,Electron mobility ,Physics and Astronomy (miscellaneous) ,Condensed Matter - Mesoscale and Nanoscale Physics ,FOS: Physical sciences ,Capacitance spectroscopy ,Field effect ,Applied Physics (physics.app-ph) ,02 engineering and technology ,Electron ,Physics - Applied Physics ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,7. Clean energy ,Capacitance ,0104 chemical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Field-effect transistor ,Atomic physics ,0210 nano-technology - Abstract
We have measured both the current-voltage ($I_\mathrm{SD}$-$V_\mathrm{GS}$) and capacitance-voltage ($C$-$V_\mathrm{GS}$) characteristics of a $\mathrm{MoS_2-LiNbO_3}$ field effect transistor. From the measured capacitance we calculate the electron surface density and show that its gate voltage dependence follows the theoretical prediction resulting from the two-dimensional free electron model. This model allows us to fit the measured $I_\mathrm{SD}$-$V_\mathrm{GS}$ characteristics over the \emph{entire range} of $V_\mathrm{GS}$. Combining this experimental result with the measured current-voltage characteristics, we determine the field effect mobility as a function of gate voltage. We show that for our device this improved combined approach yields significantly smaller values (more than a factor of 4) of the electron mobility than the conventional analysis of the current-voltage characteristics only., to appear in Applied Physics Letters
- Published
- 2017
31. Dynamic Acoustic Control of Individual Optically Active Quantum Dot-like Emission Centers in Heterostructure Nanowires
- Author
-
Michael Heigl, Jörg B. Kinzel, Achim Wixforth, Gerhard Abstreiter, Matthias Weiß, Gregor Koblmüller, Max Bichler, Hubert J. Krenner, Markus Döblinger, Daniel Rudolph, Jonathan J. Finley, Florian J. R. Schülein, and Stefanie Morkötter
- Subjects
Materials science ,Nanowire ,FOS: Physical sciences ,Bioengineering ,Molecular physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,General Materials Science ,Emission spectrum ,Quantum tunnelling ,Condensed Matter - Materials Science ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Mechanical Engineering ,Surface acoustic wave ,Materials Science (cond-mat.mtrl-sci) ,Heterojunction ,General Chemistry ,Nanosecond ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Quantum dot ,Radio frequency ,Quantum Physics (quant-ph) ,Optics (physics.optics) ,Physics - Optics - Abstract
We probe and control the optical properties of emission centers forming in radial het- erostructure GaAs-Al0.3Ga0.7As nanowires and show that these emitters, located in Al0.3Ga0.7As layers, can exhibit quantum-dot like characteristics. We employ a radio frequency surface acoustic wave to dynamically control their emission energy and occupancy state on a nanosec- ond timescale. In the spectral oscillations we identify unambiguous signatures arising from both the mechanical and electrical component of the surface acoustic wave. In addition, differ- ent emission lines of a single quantum dot exhibit pronounced anti-correlated intensity oscilla- tions during the acoustic cycle. These arise from a dynamically triggered carrier extraction out of the quantum dot to a continuum in the radial heterostructure. Using finite element modeling and Wentzel-Kramers-Brillouin theory we identify quantum tunneling as the underlying mech- anism. These simulation results quantitatively reproduce the observed switching and show that in our systems these quantum dots are spatially separated from the continuum by > 10.5 nm., This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Nano Letters, copyright \c{copyright} American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/nl4040434
- Published
- 2014
32. Site-Selective Ion Beam Synthesis and Optical Properties of Individual CdSe Nanocrystal Quantum Dots in a SiO2 Matrix
- Author
-
Hubert J. Krenner, Helmut Karl, and H. Moritz Mangold
- Subjects
Materials science ,Photoluminescence ,Silicon photonics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Ion beam ,Cadmium selenide ,business.industry ,Physics::Medical Physics ,FOS: Physical sciences ,Physics::Optics ,Nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Ion ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Nanocrystal ,chemistry ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Physics::Accelerator Physics ,Optoelectronics ,General Materials Science ,Diffusion (business) ,business - Abstract
Cadmium selenide nanocrystal quantum dots (NC-QDs) are site-selectively synthesized by sequential ion beam implantation of selenium and cadmium ions in a SiO2 matrix through sub-micron apertures followed by a rapid thermal annealing step. The size, areal density and optical emission energy of the NC-QDs are controlled by the ion fluence during implantation and the diameter of implantation aperture. For low fluences and small apertures the emission of these optically active emitters is blue-shifted compared to that of the bulk material by $>100\,{\rm meV}$ due to quantum confinement. The emission exhibits spectral diffusion and blinking on a second timescales as established also for solution synthesized NC-QDs.
- Published
- 2014
33. Probing ultrafast carrier tunneling dynamics in individual quantum dots and molecules
- Author
-
M. Zecherle, Gerhard Abstreiter, José M. Villas-Bôas, Johannes S. Wildmann, Timo Kaldewey, A. Bechtold, C. Ruppert, Hubert J. Krenner, Max Bichler, Jonathan J. Finley, Markus Betz, and Kai Müller
- Subjects
Physics ,Quantum dot ,Exciton ,Scanning tunneling spectroscopy ,General Physics and Astronomy ,Charge carrier ,Stimulated emission ,Electron ,Electric current ,Atomic physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Quantum tunnelling - Abstract
Ultrafast pump-probe spectroscopy is employed to directly monitor the tunneling of charge carriers from single and vertically coupled quantum dots and probe intra-molecular dynamics. Immediately after resonant optical excitation, several peaks are observed in the pump-probe spectrum arising from Coulomb interactions between the photogenerated charge carriers. The influence of few-Fermion interactions in the photoexcited system and the temporal evolution of the optical response is directly probed in the time domain. In addition, the tunneling times for electrons and holes from the QD nanostructure are independently determined. In polarization resolved measurements, near perfect Pauli-spin blockade is observed in the spin-selective absorption spectrum as well as stimulated emission. While electron and hole tunneling from single quantum dots is shown to be well explained by the WKB formalism, for coupled quantum dots pronounced resonances in the electron tunneling rate are observed arising from elastic and inelastic electron tunneling between the different dots.
- Published
- 2012
34. Thermochromic modulation of surface plasmon polaritons in vanadium dioxide nanocomposites
- Author
-
C. Ruppert, Helmut Karl, Markus Betz, Thorben Jostmeier, Moritz Mangold, Hubert J. Krenner, and Johannes Zimmer
- Subjects
Materials science ,Physics::Optics ,02 engineering and technology ,Grating ,01 natural sciences ,010309 optics ,Condensed Matter::Materials Science ,Optics ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,ddc:530 ,Thin film ,Diffraction grating ,Plasmon ,Total internal reflection ,Condensed Matter::Other ,business.industry ,Surface plasmon ,021001 nanoscience & nanotechnology ,Surface plasmon polariton ,Atomic and Molecular Physics, and Optics ,Optoelectronics ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,business ,Refractive index - Abstract
We propose and implement a new concept for thermochromic plasmonic elements. It is based on vanadium dioxide (VOsub2/sub) nanocrystals located in the near field of surface plasmon polaritons supported by an otherwise unstructured gold thin film. When the VOsub2/subundergoes the metal-insulator phase transition, the coupling conditions for conversion of light into propagating surface plasmon polaritons change markedly. In particular, we realize thermochromic plasmonic grating couplers with substantial switching contrast as well as tunable plasmonic couplers in a Kretschmann configuration. The use of VOsub2/subnanocrystals permits highly repetitive switching and room temperature operation. Simulations based on the actual dielectric function of our VOsub2/subnanocrystals agree well with the experiment.
- Published
- 2016
35. Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots
- Author
-
J. Daniels, Kai Müller, Martin Bichler, Paweł Machnikowski, Krzysztof Gawarecki, K. Oberhofer, Tilmann Kuhn, Jonathan J. Finley, P. L. Ardelt, Hubert J. Krenner, A. Bechtold, F. Klotz, A. M. Waeber, and General practice
- Subjects
Physics ,Exciton ,General Physics and Astronomy ,02 engineering and technology ,Electron ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Molecular physics ,Atomic orbital ,Quantum dot ,Electric field ,0103 physical sciences ,Coulomb ,ddc:530 ,Atomic physics ,010306 general physics ,0210 nano-technology ,Wave function ,Biexciton - Abstract
We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k·p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.
- Published
- 2016
36. Surface acoustic wave regulated single photon emission from a coupled quantum dot-nanocavity system
- Author
-
Michael Kaniber, Matthias Weiß, Achim Wixforth, Hubert J. Krenner, Stephan Kapfinger, T. Reichert, and Jonathan J. Finley
- Subjects
Photon ,Physics and Astronomy (miscellaneous) ,Physics::Optics ,FOS: Physical sciences ,02 engineering and technology ,Applied Physics (physics.app-ph) ,Purcell effect ,01 natural sciences ,symbols.namesake ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,010306 general physics ,Quantum optics ,Physics ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Surface acoustic wave ,Resonance ,Physics - Applied Physics ,021001 nanoscience & nanotechnology ,Coupling (physics) ,Fourier transform ,Quantum dot ,symbols ,Atomic physics ,0210 nano-technology ,Quantum Physics (quant-ph) ,Physics - Optics ,Optics (physics.optics) - Abstract
A coupled quantum dot--nanocavity system in the weak coupling regime of cavity quantumelectrodynamics is dynamically tuned in and out of resonance by the coherent elastic field of a $f_{\rm SAW}\simeq800\,\mathrm{MHz}$ surface acoustic wave. When the system is brought to resonance by the sound wave, light-matter interaction is strongly increased by the Purcell effect. This leads to a precisely timed single photon emission as confirmed by the second order photon correlation function $g^{(2)}$. All relevant frequencies of our experiment are faithfully identified in the Fourier transform of $g^{(2)}$, demonstrating high fidelity regulation of the stream of single photons emitted by the system., Comment: revised manuscript - to be published in Applied Physics Letters
- Published
- 2016
- Full Text
- View/download PDF
37. Ultrafast photodetection in the quantum wells of single AlGaAs/GaAs-based nanowires
- Author
-
Helmut Karl, Stefanie Morkötter, Jonathan J. Finley, Alexander W. Holleitner, Gerhard Abstreiter, Nadine Erhard, Gregor Koblmüller, Daniel Rudolph, Matthias Weiss, Hubert J. Krenner, and Stefan Zenger
- Subjects
Photocurrent ,Materials science ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Condensed Matter::Other ,Mechanical Engineering ,Nanowire ,FOS: Physical sciences ,Schottky diode ,Physics::Optics ,Bioengineering ,General Chemistry ,Photodetection ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Materials Science ,Semiconductor ,Picosecond ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Physics::Atomic and Molecular Clusters ,Optoelectronics ,General Materials Science ,Charge carrier ,business ,Quantum well - Abstract
We investigate the ultrafast optoelectronic properties of single Al0.3Ga0.7As/GaAs-core-shell-nanowires. The nanowires contain GaAs-based quantum wells. For a resonant excitation of the quantum wells, we find a picosecond photocurrent which is consistent with an ultrafast lateral expansion of the photogenerated charge carriers. This Dember-effect does not occur for an excitation of the GaAs-based core of the nanowires. Instead, the core exhibits an ultrafast displacement current and a photo-thermoelectric current at the metal Schottky contacts. Our results uncover the optoelectronic dynamics in semiconductor core-shell nanowires comprising quantum wells, and they demonstrate the possibility to use the low-dimensional quantum well states therein for ultrafast photoswitches and photodetectors.
- Published
- 2015
38. Scalable fabrication of a hybrid field-effect and acousto-electric device by direct growth of monolayer MoS2/LiNbO3
- Author
-
John Mann, I-Hsi Lu, David Barroso, Wladislaw Michailow, Hubert J. Krenner, Benjamin Möller, Ariana E. Nguyen, Gretel von Son, Achim Wixforth, Velveth Klee, Ludwig Bartels, Edwin Preciado, Miguel Isarraraz, and Florian J. R. Schülein
- Subjects
Materials science ,Lithium niobate ,General Physics and Astronomy ,Field effect ,Nanotechnology ,02 engineering and technology ,Substrate (electronics) ,7. Clean energy ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Article ,law.invention ,chemistry.chemical_compound ,law ,0103 physical sciences ,Monolayer ,ddc:530 ,010302 applied physics ,Multidisciplinary ,Surface acoustic wave ,Transistor ,General Chemistry ,Acoustic wave ,021001 nanoscience & nanotechnology ,chemistry ,Radio frequency ,0210 nano-technology - Abstract
Lithium niobate is the archetypical ferroelectric material and the substrate of choice for numerous applications including surface acoustic wave radio frequencies devices and integrated optics. It offers a unique combination of substantial piezoelectric and birefringent properties, yet its lack of optical activity and semiconducting transport hamper application in optoelectronics. Here we fabricate and characterize a hybrid MoS2/LiNbO3 acousto-electric device via a scalable route that uses millimetre-scale direct chemical vapour deposition of MoS2 followed by lithographic definition of a field-effect transistor structure on top. The prototypical device exhibits electrical characteristics competitive with MoS2 devices on silicon. Surface acoustic waves excited on the substrate can manipulate and probe the electrical transport in the monolayer device in a contact-free manner. We realize both a sound-driven battery and an acoustic photodetector. Our findings open directions to non-invasive investigation of electrical properties of monolayer films., Lithium niobate has piezoelectric and birefringent properties useful for optics, but it is not readily integrated with traditional optoelectronics. Here, the authors create a device that senses photoconductance in semiconducting molybdenum disulfide using surface acoustic waves excited in lithium niobate.
- Published
- 2015
39. Dynamic modulation of photonic crystal nanocavities using gigahertz acoustic phonons
- Author
-
Hubert J. Krenner, Susanna M. Thon, D. A. Fuhrmann, Achim Wixforth, Pierre Petroff, Dirk Bouwmeester, and Hyochul Kim
- Subjects
FOS: Physical sciences ,Physics::Optics ,02 engineering and technology ,01 natural sciences ,Quality (physics) ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,ddc:530 ,010306 general physics ,Photonic crystal ,Physics ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Acoustic Phonons ,Acoustic wave ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Dynamic modulation ,Optoelectronics ,Quantum Physics (quant-ph) ,0210 nano-technology ,business ,Order of magnitude ,Physics - Optics ,Optics (physics.optics) - Abstract
Photonic crystal membranes (PCM) provide a versatile planar platform for on-chip implementations of photonic quantum circuits. One prominent quantum element is a coupled system consisting of a nanocavity and a single quantum dot (QD) which forms a fundamental building block for elaborate quantum information networks and a cavity quantum electrodynamic (cQED) system controlled by single photons. So far no fast tuning mechanism is available to achieve control within the system coherence time. Here we demonstrate dynamic tuning by monochromatic coherent acoustic phonons formed by a surface acoustic wave (SAW) with frequencies exceeding 1.7 gigahertz, one order of magnitude faster than alternative approaches. We resolve a periodic modulation of the optical mode exceeding eight times its linewidth, preserving both the spatial mode profile and a high quality factor. Since PCMs confine photonic and phononic excitations, coupling optical to acoustic frequencies, our technique opens ways towards coherent acoustic control of optomechanical crystals., Comment: 11 pages 4 figures
- Published
- 2011
40. Quantum posts with tailored structural, electronic and optical properties for optoelectronic and quantum electronic device applications
- Author
-
Hubert J. Krenner and Pierre Petroff
- Subjects
Fabrication ,Photoluminescence ,Materials science ,Nanostructure ,business.industry ,Exciton ,Physics::Optics ,General Chemistry ,Electronic structure ,Condensed Matter Physics ,Dipole ,Quantum dot ,Materials Chemistry ,Optoelectronics ,ddc:530 ,business ,Quantum - Abstract
This article reviews the fabrication, structural and optical properties of self-assembled In(Ga)As quantum posts. We introduce the growth mechanism and present the resulting structural properties and electronic structure which provides a direct route to tunable intraband transitions. We show that in the interband spectrum, sharp optical transitions, single photon emission and tailored giant electrostatic dipole moments are observed. We demonstrate that these properties can be used for an exciton memory.
- Published
- 2009
41. Alloy Fluctuations Act as Quantum Dot-like Emitters in GaAs-AlGaAs Core–Shell Nanowires
- Author
-
Hubert J. Krenner, Stefanie Morkoetter, Lincoln J. Lauhon, Bernhard Loitsch, Gregor Koblmueller, Gerhard Abstreiter, Nari Jeon, and Jonathan J. Finley
- Subjects
Materials science ,Photoluminescence ,business.industry ,Exciton ,General Engineering ,Nanowire ,General Physics and Astronomy ,Heterojunction ,Atom probe ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Crystallographic defect ,law.invention ,Condensed Matter::Materials Science ,Quantum dot ,law ,Optoelectronics ,General Materials Science ,Emission spectrum ,business - Abstract
GaAs-AlxGa1-xAs (AlGaAs) core-shell nanowires show great promise for nanoscale electronic and optoelectronic devices, but the application of these nonplanar heterostructures in devices requires improved understanding and control of nanoscale alloy composition and interfaces. Multiple researchers have observed sharp emission lines of unknown origin below the AlGaAs band edge in photoluminescence (PL) spectra of core-shell nanowires; point defects, alloy composition fluctuations, and self-assembled quantum dots have been put forward as candidate structures. Here we employ laser-assisted atom probe tomography to reveal structural and compositional features that give rise to the sharp PL emission spectra. Nanoscale ellipsoidal Ga-enriched clusters resulting from random composition fluctuations are identified in the AlGaAs shell, and their compositions, size distributions, and interface characteristics are analyzed. Simulations of exciton transition energies in ellipsoidal quantum dots are used to relate the Ga nanocluster distribution with the distribution of sharp PL emission lines. We conclude that the Ga rich clusters can act as discrete emitters provided that the major diameter is ≥4 nm. Smaller clusters are under-represented in the PL spectrum, and spectral lines of larger clusters are broadened, due to quantum tunneling between clusters.
- Published
- 2015
42. Dynamic acousto-optic control of a strongly coupled photonic molecule
- Author
-
Kai Müller, Michael Kaniber, S. Lichtmannecker, Thorsten Reichert, Jonathan J. Finley, Achim Wixforth, Stephan Kapfinger, and Hubert J. Krenner
- Subjects
Physics ,Multidisciplinary ,business.industry ,Surface acoustic wave ,Nanophotonics ,Physics::Optics ,General Physics and Astronomy ,Nanotechnology ,General Chemistry ,Article ,General Biochemistry, Genetics and Molecular Biology ,ddc ,Coupling (physics) ,Quantum gate ,Optoelectronics ,ddc:530 ,Radio frequency ,Photonics ,business ,Quantum ,Photonic crystal - Abstract
Strongly confined photonic modes can couple to quantum emitters and mechanical excitations. To harness the full potential in quantum photonic circuits, interactions between different constituents have to be precisely and dynamically controlled. Here, a prototypical coupled element, a photonic molecule defined in a photonic crystal membrane, is controlled by a radio frequency surface acoustic wave. The sound wave is tailored to deliberately switch on and off the bond of the photonic molecule on sub-nanosecond timescales. In time-resolved experiments, the acousto-optically controllable coupling is directly observed as clear anticrossings between the two nanophotonic modes. The coupling strength is determined directly from the experimental data. Both the time dependence of the tuning and the inter-cavity coupling strength are found to be in excellent agreement with numerical calculations. The demonstrated mechanical technique can be directly applied for dynamic quantum gate operations in state-of-the-art-coupled nanophotonic, quantum cavity electrodynamic and optomechanical systems., Dynamic control of components is required for large-scale quantum photonic networks. Here, Kapfinger et al. show dynamic control of the interaction between two coupled photonic crystal nanocavities forming a photonic molecule. Tuning is achieved by using an electrically generated radio frequency surface acoustic wave.
- Published
- 2015
43. Nonequilibrium carrier dynamics in self-assembled InGaAs quantum dots
- Author
-
Markus Betz, S. Trumm, C. Ruppert, Jonathan J. Finley, M. Wesseli, and Hubert J. Krenner
- Subjects
Photoluminescence ,Condensed matter physics ,Chemistry ,Phonon ,Physics::Optics ,Electronic structure ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,Quantum dot laser ,Quantum dot ,Excited state ,Femtosecond ,ddc:530 ,Wetting layer - Abstract
Carrier dynamics in InGaAs/GaAs quantum dots is analyzed with highly sensitive femtosecond transmission spectroscopy. In a first step, measurements on a large ensemble of nanoislands reveal the dynamical electronic filling of quantum dots from the surrounding wetting layer. Most interestingly, we find a spin-preserving phonon mediated scattering into fully localized states within a few picoseconds. Then, individual artificial atoms are isolated with metallic shadow masks. For the first time, a single self-assembled quantum dot is addressed in an ultrafast transmission experiment. We find bleaching signals in the order of 10 -5 that arise from individual interband transitions of one quantum dot. As a result, we have developed an ultrafast optical tool for both manipulation and read-out of a single self-assembled quantum dot.
- Published
- 2006
44. Investigation of cavity modes and direct observation of Purcell enhancement in 2D photonic crystal defect microcavities
- Author
-
F. Hofbauer, Hubert J. Krenner, N. Reinelt, Gerhard Abstreiter, Martin Bichler, Ralf Meyer, Jonathan J. Finley, Dieter Schuh, and A. Kress
- Subjects
Coupling ,Mode volume ,Materials science ,business.industry ,Direct observation ,Physics::Optics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Optical microcavity ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,law ,Quantum dot ,Physics::Accelerator Physics ,Optoelectronics ,ddc:530 ,Hexagonal lattice ,Spontaneous emission ,business ,Photonic crystal - Abstract
We demonstrate our ability to control and manipulate the optical modes in 2D Photonic Crystal Defect cavities and investigate their coupling to InGaAs self-assembled quantum dots. Our results enable us to probe the nature of individual cavity modes and directly investigate cavity QED phenomena. For the lowest mode volume cavities investigated, consisting of a single missing air hole within a hexagonal lattice, we have measured a clear Purcell enhancement of the light-matter interaction in the weak coupling regime. For QDs on-resonance with localized cavity modes this translates to a shortening of the quantum dot spontaneous emission lifetime by a factor ∼2 when compared to off-resonance dots.
- Published
- 2005
45. Two-color Femtosecond Spectroscopy of Blue-Shifted InAs/AlGaAs Quantum Dots
- Author
-
Martin Bichler, Markus Betz, Artur Zrenner, E. Beham, Gerhard Abstreiter, S. Trumm, Alfred Leitenstorfer, and Hubert J. Krenner
- Subjects
Physics ,business.industry ,Quantum point contact ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,Quantum dot ,Quantum dot laser ,Excited state ,Femtosecond ,Optoelectronics ,ddc:530 ,Quantum-optical spectroscopy ,business ,Ground state ,Wetting layer - Abstract
Ultrafast relaxation phenomena in self-organized InAs/AlGaAs quantum dots with ground state transition energies of 1.42 eV are analyzed with different methods of femtosecond spectroscopy. A time-correlated luminescence experiment of an ensemble of InAs islands reveals a picosecond relaxation mechanism of carriers within the quantum dots. Moreover, modifications of the quantum dot properties due to excitation of the surrounding wetting layer is found. Employing a shadow-mask technique, a structure containing only a few zero-dimensional objects is studied. Selectively creating electron-hole pairs in excited states of approximately ten quantum dots, we observe characteristic line shifts of their ground state absorption in a two-color femtosecond transmission experiment. This finding demonstrates the feasibility of ultrafast studies of single self-assembled quantum dots.
- Published
- 2002
46. Multi-harmonic quantum dot optomechanics in fused LiNbO3–(Al)GaAs hybrids
- Author
-
Yongheng Huo, Armando Rastelli, Hailong Yu, Emeline D. S. Nysten, Hubert J. Krenner, and Guo Feng Song
- Subjects
Materials science ,Acoustics and Ultrasonics ,Physics::Optics ,FOS: Physical sciences ,Applied Physics (physics.app-ph) ,02 engineering and technology ,01 natural sciences ,7. Clean energy ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,010306 general physics ,Optomechanics ,Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,business.industry ,Physics - Applied Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Quantum dot ,Harmonic ,Optoelectronics ,Quantum Physics (quant-ph) ,0210 nano-technology ,business ,Physics - Optics ,Optics (physics.optics) - Abstract
We fabricated an acousto-optic semiconductor hybrid device for strong optomechanical coupling of individual quantum emitters and a surface acoustic wave. Our device comprises a surface acoustic wave chip made from highly piezoelectric LiNbO$_3$ and a GaAs-based semiconductor membrane with an embedded layer of quantum dots. Employing multi-harmonic transducers, we generated sound waves on LiNbO$_3$ over a wide range of radio frequencies. We monitored their coupling to and propagation across the semiconductor membrane both in the electrical and optical domain. We demonstrate enhanced optomechanical tuning of the embedded quantum dots with increasing frequencies. This effect was verified by finite element modelling of our device geometry and attributed to an increased localization of the acoustic field within the semiconductor membrane. For moderately high acoustic frequencies, our simulations predict strong optomechanical coupling making our hybrid device ideally suited for applications in semiconductor based quantum acoustics., Comment: revised manuscript. unit conversion error fixed
- Published
- 2017
47. Radio frequency occupancy state control of a single nanowire quantum dot
- Author
-
Jörg B. Kinzel, Achim Wixforth, Hubert J. Krenner, Florian J. R. Schülein, Max Bichler, Daniel Rudolph, Jonathan J. Finley, Gerhard Abstreiter, Matthias Weiß, Gregor Koblmüller, and Michael Heigl
- Subjects
Physics ,Quantum Physics ,Acoustics and Ultrasonics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Exciton ,Surface acoustic wave ,Nanowire ,FOS: Physical sciences ,Heterojunction ,Electron ,Condensed Matter Physics ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Molecular physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Wavelength ,Condensed Matter::Materials Science ,Quantum dot ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,ddc:530 ,Radio frequency ,Quantum Physics (quant-ph) ,Optics (physics.optics) ,Physics - Optics - Abstract
The excitonic occupancy state of a single, nanowire-based, heterostructure quantum dot is dynamically programmed by a surface acoustic wave. The quantum dot is formed by an interface or thickness fluctuation of a GaAs QW embedded in a AlGaAs shell of a GaAs-AlGaAs core-shell nanowire. As we tune the time at which carriers are photogenerated during the acoustic cycle, we find pronounced intensity oscillations of neutral and negatively charged excitons. At high acoustic power levels these oscillations become anticorrelated which enables direct acoustic programming of the dot's charge configuration, emission intensity and emission wavelength. Numerical simulations confirm that the observed modulations arise from acoustically controlled modulations of the electron and electron-hole-pair concentrations at the position of the quantum dot., Revised manuscript, 12 pages, submitted to J. Phys. D as a contribution in a Special Issue on Nanowires
- Published
- 2014
48. Entanglement creation in a quantum-dot–nanocavity system by Fourier-synthesized acoustic pulses
- Author
-
Ralf Blattmann, Hubert J. Krenner, Peter Hänggi, Sigmund Kohler, and Ministerio de Economía y Competitividad (España)
- Subjects
Physics ,Photon ,Dephasing ,Surface acoustic wave ,Physics::Optics ,Quantum entanglement ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Atomic and Molecular Physics, and Optics ,Superposition principle ,Quantum dot ,Quantum mechanics ,Master equation ,ddc:530 ,Atomic physics ,Photonic crystal - Abstract
We explore the possibility of entangling an excitonic two-level system in a semiconductor quantum dot with a cavity defined on a photonic crystal by sweeping the cavity frequency across its resonance with the exciton transition. The dynamic cavity detuning is established by a radio frequency surface acoustic wave (SAW). It induces Landau-Zener transitions between the excitonic and the photonic degrees of freedom and thereby creates a superposition state. We optimize this scheme by using tailored Fourier-synthesized SAW pulses with up to five harmonics. The theoretical study is performed with a master equation approach for present state-of-the-art setups. Assuming experimentally demonstrated system parameters, we show that the composed pulses increase both the maximum entanglement and its persistence. The latter is only limited by the dominant dephasing mechanism, i.e., the photon loss from the cavity. © 2014 American Physical Society., We gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG) via Sonderforschungsbereich SFB 631 (Projects No. A5 and No. B5) and the Emmy Noether Program (HJK, KR3790/2-1). This work was supported by the Spanish Ministry of Economy and Competitiveness via Grant No. MAT2011-24331.
- Published
- 2014
49. Site-selective ion beam synthesis and optical properties of individual CdSe nanocrystal quantum dots in a SiO₂ matrix
- Author
-
H Moritz, Mangold, Helmut, Karl, and Hubert J, Krenner
- Abstract
Cadmium selenide nanocrystal quantum dots (NC-QDs) are site-selectively synthesized by sequential ion beam implantation of selenium and cadmium ions in a SiO2 matrix through submicrometer apertures followed by a rapid thermal annealing step. The structural and optical properties of the NC-QDs are controlled by the ion fluence during implantation and the diameter of the implantation aperture. For low fluences and small apertures the emission of these optically active emitters is blue-shifted compared to that of the bulk material by100 meV due to quantum confinement. The emission exhibits spectral diffusion and blinking on a second time scales as established also for solution-synthesized NC-QDs.
- Published
- 2014
50. Radio Frequency Electromechanical Control over a Surface Plasmon Polariton Coupler
- Author
-
Frederike Förster, Jörg B. Kinzel, Achim Wixforth, C. Ruppert, Hubert J. Krenner, Markus Betz, and Artur Zrenner
- Subjects
Physics ,business.industry ,Surface acoustic wave ,Surface plasmon ,Ripple ,Physics::Optics ,Acoustic wave ,Grating ,Surface plasmon polariton ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Surface acoustic wave sensor ,Electrical and Electronic Engineering ,business ,Plasmon ,Biotechnology - Abstract
We explore the impact of ∼500 MHz surface acoustic waves traveling across a commensurable plasmonic grating coupler. A stroboscopic technique involving surface acoustic waves synchronized to a modelocked optical source allows to time-resolve the dynamical impact of the electromechanically induced perturbation. The surface acoustic wave periodically enhances or decreases the surface ripple of the static grating. Most remarkably, the dynamic surface deformation deliberately modulates the coupler’s efficiency by ±2% during the ∼2 ns acoustic cycle.
- Published
- 2014
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.