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We demonstrated a passively Q-switched Nd: LuAG laser at 1064 nm based on few-layered MoS 2 saturable absorber (SA) for the first time. The output pulses with a pulse duration of 280 ns and a repetition rate of 210 kHz were obtained at an incident pump power of 7.3 W, corresponding to a maximum output power of 290 mW. The experimental results show that MoS 2 is a promising SA for solid-state lasers at 1 μ m. [ABSTRACT FROM AUTHOR]

We demonstrate a passively Q-switched solid-state laser operating at the central wavelength of 1342 nm based on gold nanobipyramids (Au-NBPs) as saturable absorber (SA) for the first time. Au-NBPs are fabricated through a seed-mediated growth method, and placed in a simple linear cavity. Under an absorbed diode-pumped power of 5.339 W, an average power of 175 mW was generated with a minimum pulse width of 342 ns and a repetition rate of 141.8 kHz, corresponding to a pulse energy of 1.23 μ J. [ABSTRACT FROM AUTHOR]

Photonic nanocavities in diamond have emerged as useful structures for interfacing photons and embedded atomic color centers, such as the nitrogen vacancy center. Here, we present a hybrid nanocavity design that enables (i) a loaded quality factor exceeding 50 000 (unloaded Q > 106) with 75% of the enhanced emission collected into an underlying waveguide circuit, (ii) MEMS-based cavity spectral tuning without straining the diamond, and (iii) the use of a diamond waveguide with straight sidewalls to minimize surface defects and charge traps. This system addresses the need for scalable on-chip photonic interfaces to solidstate quantum emitters. [ABSTRACT FROM AUTHOR]

We discuss a scheme for the coherent control of light and plasmons in nanoparticles that have nonlocal dielectric permittivity and contain nonlinear impurities or color centers. We consider particles which have a response to light that is strongly influenced by plasmons over a broad range of frequencies. Our coherent control method enables the reduction of absorption and/or suppression of scattering. [ABSTRACT FROM AUTHOR]

Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields. [ABSTRACT FROM AUTHOR]

Photothermal effects in a holographic medium of calcium fluoride crystals with color centers $$(\hbox {CaF}_{2})$$ are discussed. It is shown that photochromism of this crystal makes it possible to record volume holograms within its volume and to change their physical properties by photothermal treatments. The diffusion-drift mechanism of a hologram recording in $$\hbox {CaF}_{2}$$ includes the conversion of centers and their redistribution over the crystal bulk. Depending on the readout wavelength, it is possible to read out amplitude, amplitude phase, or phase holograms. The opportunity to record thick holograms in $$\hbox {CaF}_{2}$$ and their high resistance with respect to non-coherent illumination at an elevated temperature allows forming narrow-band angular and spectral holographic filters in $$\hbox {CaF}_{2}$$ . [ABSTRACT FROM AUTHOR]

The successful growth of nanocrystalline diamond (NCD) thin films with optically active Si-related color centers was realized on glass and molybdenum substrates by the microwave plasma chemical vapor deposition (CVD) with focused or linear antenna plasma reactors. Diamond coatings were characterized by Raman spectroscopy, scanning electron microscopy, and photoluminescence (PL) spectroscopy. Increased of a-Si interlayer thickness resulted in reduction of stress in NCD film and increased renucleation of NCD films. The PL spectra showed that the Si-color center is only observed in the focused plasma system. The influence of the substrate material as well as the a-Si interlayer on the density of Si-related color center was not confirmed in our setup. [ABSTRACT FROM AUTHOR]

Abstract: A tunable narrow line-width LiF:F2 − color center laser with a Littman cavity pumped by an LD pumped Nd:YVO4 acousto-optically Q-switched laser with 30kHz pulse repetition rate was demonstrated. Under the pumped power of 0.82W, the tuning range was from 1110nm to 1215nm and the maximal average output power was 18.5mW at the wavelength of 1150nm. Stable single longitudinal mode LiF:F2 − CC laser operation was achieved with a Fabry–Perot etalon and a beam expander inside the cavity and the line-width was less than 1.5GHz. [Copyright &y& Elsevier]

The properties of near-infrared (NIR) photoluminescence (PL) spectra in a range of 0.8-2.8 µm in fast neutron-irradiated α-Al2O3 are reported. Anomalous temperature dependence of NIR PL spectra was observed in neutron-irradiated α-Al2O3 for the first time. Highest PL intensity was measured at 260K whereas the intensity at low temperatures below 220K decreased significantly. Phonon-assisted indirect radiative recombination may be responsible for PL intensity enhancement at near room temperature. NIR PL band in a range of 0.8-2.8 µm may be well suited for application in broadly tunable color-center laser because of its enhanced PL intensity at near room temperature. [ABSTRACT FROM AUTHOR]

The properties of near-infrared (NIR) photoluminescence (PL) spectra in a range of 0.8-2.8 µm in fast neutron-irradiated α-Al2O3 are reported. Anomalous temperature dependence of NIR PL spectra was observed in neutron-irradiated α-Al2O3 for the first time. Highest PL intensity was measured at 260K whereas the intensity at low temperatures below 220K decreased significantly. Phonon-assisted indirect radiative recombination may be responsible for PL intensity enhancement at near room temperature. NIR PL band in a range of 0.8-2.8 µm may be well suited for application in broadly tunable color-center laser because of its enhanced PL intensity at near room temperature. [ABSTRACT FROM AUTHOR]

Abstract: The nitrogen-vacancy (NV) colour centre in diamond is an important physical system for emergent quantum technologies, including quantum metrology, information processing and communications, as well as for various nanotechnologies, such as biological and sub-diffraction limit imaging, and for tests of entanglement in quantum mechanics. Given this array of existing and potential applications and the almost 50 years of NV research, one would expect that the physics of the centre is well understood, however, the study of the NV centre has proved challenging, with many early assertions now believed false and many remaining issues yet to be resolved. This review represents the first time that the key empirical and ab initio results have been extracted from the extensive NV literature and assembled into one consistent picture of the current understanding of the centre. As a result, the key unresolved issues concerning the NV centre are identified and the possible avenues for their resolution are examined. [Copyright &y& Elsevier]

Intensity-dependent absorption of 25 ns excimer laser pulses in common UV-window materials was investigated. By employing a calorimetric technique which provides greatly enhanced sensitivity compared to transmissive measurements, two-photon absorption coefficients were determined at intensities of 2-80 MW/cm2 and found to be in good agreement with previous measurements at 10-100 GW/cm2. Also, color-center formation in fused silica was observed. It was possible to quantify transient and cumulative effects as a function of intensity. [ABSTRACT FROM AUTHOR]

The effect of the birefringence of an intracavity diamond heat spreader on the lasing performance of a vertical external cavity surface emitting laser is investigated. The birefringence in the intra-cavity diamond caused considerable additional round-trip loss when a birefringent filter was inserted into the cavity. The effect of the birefringence of intra-cavity diamond can be reduced by rotation of the sample. By aligning the axes of the diamond birefringence and those of the Brewster surfaces, a pump-power limited green output power of 5.2 W was achieved – a pump to green conversion efficiency of 24%. [ABSTRACT FROM AUTHOR]

Color centers in diamond are promising solid-state qubits for scalable quantum photonics applications. Amongst many defects, those with inversion symmetry are of an interest due to their promising optical properties. In this work, we demonstrate a maskless implantation of an array of bright, single germanium vacancy (GeV) centers in diamond. Employing the direct focused ion beam technique, single GeV emitters are engineered with the spatial accuracy of tens of nanometers. The single GeV creation ratio reaches as high as 53% with the dose of 200 Ge+ ions per spot. The presented fabrication method is promising for future nanofabrication of integrated photonic structures with GeV emitters as a leading platform for spin-spin interactions. [ABSTRACT FROM AUTHOR]

The negatively charged silicon vacancy (SiV) color center in diamond has recently proven its suitability for bright and stable single photon emission. However, its electronic structure so far has remained elusive. We here explore the electronic structure by exposing single SiV defects to a magnetic field where the Zeeman effect lifts the degeneracy of magnetic sublevels. The similar responses of single centers and a SiV ensemble in a low strain reference sample prove our ability to fabricate almost perfect single SiVs, revealing the true nature of the defect's electronic properties. We model the electronic states using a group-theoretical approach yielding a good agreement with the experimental observations. Furthermore, the model correctly predicts polarization measurements on single SiV centers and explains recently discovered spin selective excitation of SiV defects. [ABSTRACT FROM AUTHOR]