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We present an integrated magneto-photonic device for all-optical switching of non-volatile multi-bit spintronic memory. The bits are based on stand-alone magneto-tunnel junctions, which are perpendicularly magnetized with all-optically switchable free layers, coupled onto photonic crystal nanobeam cavities on an indium phosphide based platform. This device enables switching of the magnetization state of the bits by locally increasing the power absorption of light at resonance with the cavity. We design an add/drop network of cavities to grant random access to multiple bits via a wavelength-division multiplexing scheme. Based on a three-dimensional finite-difference time-domain method, we numerically illustrate a compact device capable of switching and accessing at least eight bits in different cavities with a 5 nm wavelength spacing in the conventional (C) telecommunication band. Our multi-bit device holds promise as a new paradigm for developing an ultrafast photonically addressable spintronic memory and may also empower novel opportunities for photonically driven spintronic-based neuromorphic computing. [ABSTRACT FROM AUTHOR]

In this research, we propose a simple and novel graphene-black phosphorus composite structure. Through the coupling mechanism of bright–bright mode, four layers of graphene and one layer of black phosphorus produce a quadruple plasmon-induced transparency (PIT) effect. The response of the proposed structure to the angle of polarized light is investigated, and it is found that the sensitivities of graphene and black phosphorus to the polarization angle of light are different. In addition, the dynamic regulation of PIT by the Fermi level of graphene and the carrier concentration of black phosphorus are discussed. The modulation depths of the fivefold optical switching are 96%, 99%, 87%, 93%, and 80%, respectively. The quadruple PIT can also be converted into triple PIT, in which single, dual, or triple optical switching are realized, respectively. Finally, with the change in the refractive index of the environment medium, the sensitivity response of the proposed structure is as high as 4.790 THz⋅RIU−1. We believe that this research will contribute to the development of optical switches, modulators, and sensors. [ABSTRACT FROM AUTHOR]

We report microsecond timescale switching between the superconducting and normal states of commercially manufactured high-T c superconducting wires using optical radiation to heat the conductor above T c. The achieved voltages and switching times have significant implications for a new class of thermal switches. The report contains experimental data for photo-induced microsecond scale voltage transients as well as numerical analysis of heat propagation through the material in response to optical radiation. The microbridges are etched into commercially manufactured coated conductors and submerged in liquid nitrogen. By varying the magnitude of the transport current, two different optical responses are identified. At low transport currents, short-lived voltage transients occur, transitioning to persistent latching once the current is increased above a threshold value. The microbridge, therefore, behaves as a fast opening and closing switch when carrying low currents or an optically latched thyristor at high currents. This is understood to occur due to critical current suppression as a result of heating from the optical pulse. Optically induced heating reduces the superconducting volume fraction, and Joule heating due to the transport current interaction with the high temperature superconducting occurs, which either causes short-lived or stable self-heating normal regions dependent on the magnitude of the transport current. This study is concluded with an estimate of the energy necessary to drive the microbridge into the resistive state. The observed behavior can potentially be utilized as a switching element in superconducting transformer rectifiers where high frequency switch operation is required. [ABSTRACT FROM AUTHOR]

This paper is focused on modern optical switching, which is a subject of great interest due to the high speed, secure data processing, and compact size of modern communication systems. In the optical architecture, phase-shifted fiber Bragg grating (PSFBG) contributes additional features towards all-optical switching. This work proposes a modern communication system with an all-optical 4-bit parity checker circuit as an essential device within the framework of the FBG structure and cross-phase modulation (XPM)-based nonlinear switching performance. In the new era of modern communication systems and high-speed switching technology, PSFBG based on XPM also opens the path towards integrated optics and switch-in fiber as integrated optical communication. [ABSTRACT FROM AUTHOR]

Valley photonic crystals (VPCs) provide an intriguing approach to suppress backscattering losses and enable robust transport of light against sharp bends, which could be utilized to realize low-loss and small-footprint devices for on-chip optical communications. However, there are few studies on how to achieve power-efficient tunable devices based on VPCs, which are essential for implementing basic functions such as optical switching and routing. Here, we propose and experimentally demonstrate a thermally tunable add-drop filter (ADF) based on VPCs operating at telecommunication wavelengths. By leveraging the topological protection of the edge state and the distinct property of negligible scattering at sharp bends, a small footprint of 17.4 × 28.2 μm2 and a low insertion loss of 2.7 dB can be achieved for the proposed device. A diamond-shaped microloop resonator is designed to confine the light and enhance its interaction with the thermal field generated by the microheater, leading to a relatively low power of 23.97 mW needed for switching the output signal from one port to the other. Based on the thermally tunable ADF under the protection of band topology, robust data transmission is implemented with an ultrahigh data rate of 132 Gb/s. Our work shows great potential for developing high-performance topological photonic devices with the thermally tunable silicon-based VPCs, which offers unprecedented opportunities for realizing topologically protected and reconfigurable high-speed datalinks on a chip. [ABSTRACT FROM AUTHOR]

Ultrafast all-optical control has been a subject of wide-spread attention as a method of manipulating optical fields using light excitation on extremely short time scales. As a fundamental form of ultrafast all-optical control, all-optical switching has achieved sub-picosecond switch speeds in the visible, infrared, and terahertz spectral regions. However, due to the lack of suitable materials, ultrafast all-optical control in the ultraviolet range remains in its early stages. We demonstrate sub-picosecond all-optical switching in the ultraviolet wavelength by designing a Si3N4-ITO Fabry–Pérot resonance aligns with the edge of the interband transition region of ITO. The response time of 500 fs achieved at a pump fluence as low as 0.17 mJ/cm2. Notably, unlike conventional binary switches (0, 1), this biphasic all-optical switch enables the modulation of optical intensity with positive, zero, and negative ΔR/R (0, 1, −1) at the same wavelength, all achieved with a switching speed of 680 fs at a pump fluence of 0.45 mJ/cm2. This work establishing a new pathway for all-optical control in the ultraviolet spectrum, the biphasic switch provides an extra degree of freedom for all-optical modulation. [ABSTRACT FROM AUTHOR]

Optical phase change materials (OPCMs) hold significant promise in photonic integrated circuits (PICs) due to their non‐volatile modulation capabilities through phase transition. Recently, integrating OPCMs with silicon devices has been leveraged to achieve multi‐level modulation in neural network computing. However, the conventional OPCM Ge2Sb2Te5 (GST), faces challenges in large‐scale PICs due to its large absorption. In this work, an optimized low‐loss GST superlattice is demonstrated, which significantly lowers crystalline attenuation coefficients from 2.69 to 0.539 dB µm−1, with negligible loss in amorphous state, while retaining excellent phase modulation capability. Additionally, 15 distinguishable extinction ratio states are achieved by manipulating irradiation energy for a hybrid Si microring resonator (MRR) embedded with GST superlattice. To further explore the potential application of GST superlattice in optical computing, an all‐optical tunable temporal differentiator is empirically demonstrated with a single hybrid MRR, achieving a broad dynamic differentiation order ranging from 0.7 to 1.3. The non‐volatile nature of OPCM facilitates low energy consumption and effectively optimizes chip density. The proposed structural design strategy to reduce the absorption loss is universal for any promising OPCMs feasible for large‐scale artificial intelligence‐driven PICs, including optical analog computing, optical switching and optical neural networks. [ABSTRACT FROM AUTHOR]

In this study, we conducted the synthesis and diagnosis of compound denoted as 1A3, specifically, (2E,4E,9E,11E)-7-chloro-2,12-diphenyltrideca-2,4,9,11-tetraene-6,8-dione. The photoluminescent and UV-vis spectral properties of this compound are investigated. The compound is dissolved in both chloroform and DMF for analysis purposes. Compound 1A3's nonlinear optical (NLO) characteristics when dissolved in DMF, are extensively studied through a series of experiments including diffraction patterns (DPs) and Z-scan. The optical limiting (OL) property of the 1A3 compound is tested and a threshold value of 12.4 mW at the wavelength 473 nm is obtained. Additionally, we explored its potential for all-optical switching utilizing two low-power visible laser beams. Notably, we achieved a significant nonlinear refractive index (NLRI) reaching up to 5.921 x 10-11 m2/W. To analyze the obtained diffraction patterns, we employed the Fresnel-Kirchhoff integral equation and conducted meticulous simulations. The numerical outcomes showed satisfactory agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

In this present work we have studied the physical, structural, thermal, and optical properties of a new set of alkali zinc boro tellurite glasses doped europium trioxide prepared using the melt-quenching method. X-ray diffraction technique (XRD) and SEM were used to determine the non-crystalline property and microstructure property of the prepared samples. By using MAS-NMR spectroscopy and FTIR spectroscopy, the structural changes in the glasses were revealed. The physical properties were described by considering the densities of glass samples and hence molar volume, polaron radius, and oxygen packing density were measured. Thermal stability of glasses was perceived by performing DSC analysis and values ranges from 145 to 190 °C. Using UV–visible absorption spectra, it was possible to calculate the optical properties. The highest refractive index is found as 2.275 for glass AZBTE0 and the lowest is 2.241 for AZBTE5 glass. The ionic behaviour of the glasses was determined by electronegativity and values lie in the range of 1.51 to 1.688. The outcomes of the physical, thermal, and optical characteristics of glasses are intended for potential uses in optical switching and Europium doped fibre amplifier applications. [ABSTRACT FROM AUTHOR]

Optical microresonators supporting whispering-gallery modes (WGMs) have become a versatile platform for achieving electromagnetically induced transparency-like (EIT-like) phenomena. We theoretically and experimentally demonstrated the tunable coupled-mode induced transparency based on the surface nanoscale axial photonics (SNAP) microresonator. Single-EIT-like and double-EIT-like (DEIT-like) effects with one or more transparent windows are achieved due to dense mode families and tunable resonant frequencies. The experimental results can be well-fitted by the coupled mode theory. An automatically adjustable EIT-like effect is discovered by immersing the sensing region of the SNAP microresonator into an aqueous environment. The sharp lineshape and high slope of the transparent window allow us to achieve a liquid refractive index sensitivity of 2058.8 pm/RIU. Furthermore, we investigated a displacement sensing phenomenon by monitoring changes in the slope of the transparent window. We believe that the above results pave the way for multi-channel all-optical switching devices, multi-channel optical communications, and biochemical sensing processing. [ABSTRACT FROM AUTHOR]

Recent works have demonstrated that the optical excitation of crystalline materials with intense narrow-band infrared pulses, tailored to match the frequencies at which the crystal's permittivity approaches close to zero, can drive a permanent reversal of magnetic and ferroelectric ordering. However, the physical mechanism that microscopically underpins this effect remains unclear, as well as the precise role of laser-induced heating and macroscopic strains. Here, we explore how infrared pulses can simultaneously give rise to strong temperature-dependent birefringence and strain in ferroelectric barium titanate. We develop a model of these two coexisting effects, allowing us to use polarization microscopy to disentangle them through their spatial distributions, temporal evolutions and spectral dependencies. We experimentally observe strain-induced patterns that are an order of magnitude larger than that which can be accounted for by laser-induced heating alone, suggesting that non-thermal effects must also play a role. Our results reveal the distinct fingerprints of heat- and strain-induced birefringence, shedding new light on the process of all-optical switching of order parameters in the epsilon-near-zero regime. [ABSTRACT FROM AUTHOR]

Ultrafast thermally induced magnetization switching (TIMS) with femtosecond lasers has attracted much attention due to its ability to trigger a single switching on the picosecond time scale. Currently, most of the studies on TIMS have focused on various ferrimagnetic alloys. In this paper, TIMS of Gd/Fe multilayers in different monolayer ratios is investigated by atomic spin dynamics. The results show that an increase in the monolayer Gd ratio narrows the energy density window of the switching. Further studies found that a lower damping ratio decreases the laser energy density threshold for magnetization reversal. Moreover, reducing the ratio of Gd in the monolayer at the appropriate energy density can shorten the duration of the transient ferromagnetic-like state, which can lead to faster realization of TIMS. Our simulation results provide new insights to explore the physical mechanism of TIMS in Gd/Fe multilayers. [ABSTRACT FROM AUTHOR]

Hybrid metasurfaces incorporated by active materials hold great promise for state‐of‐the‐art terahertz functional devices. However, it is still a major challenge to achieve ultrafast, dynamic, and multifunctional effective control of THz waves via hybrid metasurfaces. Herein, a modulator consisting of split rings and cut‐wires is first demonstrated, with an amplitude of −35.6 dB at 0.524 THz. By embedding semiconductor silicon into specified locations to form a hybrid metasurface, the ultrastrong connectivity of the silicon bridges leads to rapid optical molecularization. Under photoexcitation, the frequency tuning range is 26.7%, the phase shifting reaches 357.5°, and the maximal modulation depth is 94.54%. Taking advantage of the rapid relaxation of photocarriers in the silicon bridges, the ultrafast frequency switching is within 1400 ps. More interestingly, by changing the positions of the silicon bridges, the frequency tuning range is further promoted to 60%, the phase shifting is 353.5°, the modulation depth of 100% is achieved, and the full recovery time is 1600 ps. Furthermore, the underlying mechanism of the ultrafast tuning process is elucidated. This work demonstrates the feasibility of all‐optical‐controlled hybrid metasurface to achieve multifunctional dynamic modulation of THz waves, which has tremendous potential for applications in optical switching, signal processing, and frequency conversion. [ABSTRACT FROM AUTHOR]

In this work, (Z)-2-((E)-(2-oxoindolin-3-ylidene)hydrazono)-3-phenylthiazolidin-4-one 7 (C17H12N4O2S) as a hybrid molecule is synthesized under an easy method and analytically ascertained by 1HNMR, 13CNMR, IR, Mass, and UV–vis. spectroscopies. The optimized geometry of the synthesized hybrid molecule 7 is acquired using DFT-assisted calculations involving B3LYP equation with 6-31G(d,p) as a basis set level. At the same level, TD-DFT calculations are performed to collect the theoretical UV–vis. spectrum of the hybrid molecule 7. The nonlinear optical (NLO) properties of the hybrid molecule 7 are studied under irradiation with a cw laser beam. The nonlinear refractive index (NLRI), n2, of the hybrid molecule 7 is estimated via diffraction patterns (DPs) and Z-scan. The all optical switching is tested for the hybrid molecule 7 using two, cw, laser beams. Both static and dynamic all-optical switching are studied. [ABSTRACT FROM AUTHOR]

A novel design of ultrahigh efficiency and ultralow threshold energy all-optical switches based on local state transition of complete-connected optical waveguide networks (CCOWNs) is proposed. The generation of the ultra-narrow transmission peak and the ultra-strong photonic localization in network is attributed to the mutation of states, which are significant improvements in the performance of all-optical switch. First, the ultra-strong photonic localization induces the Kerr effect in nonlinear material, which transforms the transmission peaks into a transmission valley and results in the super-high efficiency. The efficiency of switch based on CCOWN with 11 unit cell (UC) and each UC possessing 7 nodes was calculated and found to be approximately 1.38 × 10 39 , which is 13 orders of magnitude better than previously reported. Furthermore, the ultra-strong photonic localization also leads to the ultralow threshold energy. Calculations reveal that the threshold control energy of all-optical switch based on CCOWN only with 7 UC and each UC possessing 5 nodes is about 5.78 × 10 - 30 J, which is 5 orders of magnitude smaller than the best reported results. In addition, fitting formulas for the transmission and switching efficiency with UC number have been derived, and the results show that the switching efficiency increased exponentially with the UC number and nodes. This study not only presents a new model for designing all-optical switch with outstanding performance, but also provides the possibility for further practical use of all-optical switch, while deepening our insight into optical waveguide networks. [ABSTRACT FROM AUTHOR]

The control of light through all‐optical means is a fundamental challenge in nanophotonics and a key effect in optical switching and logic. The optical bistability effect enables this control and can be observed in various planar photonic systems such as microdisk and photonic crystal cavities and waveguides. However, the recent advancements in flat optics with wavelength‐thin optical elements require nonlinear elements based on metastructures and metasurfaces. The performance of these systems can be enhanced with high‐Q bound states in the continuum (BIC), which leads to intense harmonic generation, improved light‐matter coupling, and pushes forward sensing limits. This study reports enhanced thermo‐optical nonlinearity and the observation of optical bistability in an all‐dielectric metasurface membrane with BIC. Unlike many other nanophotonic platforms, metasurfaces allow for fine control of the quality factor of the BIC resonance by managing the radiative losses. This provides an opportunity to control the parameters of the observed hysteresis loop and even switch from bistability to optical discrimination by varying the angle of incidence. Additionally, this work proposes a mechanism of nonlinear critical coupling that establishes the conditions for maximal hysteresis width and minimal switching power, which has not been reported before. The study suggests that all‐dielectric metasurfaces supporting BICs can serve as a flat‐optics platform for optical switching and modulation based on strong thermo‐optical nonlinearity. [ABSTRACT FROM AUTHOR]

Much effort in the past few years has been made in tunnelling, however, no work has been reported so far on how to maintain the maximum tunnelling of complex optical fields in waveguides, due to the limitations of existing physical mechanisms. Here, a new paradigm is presented for realizing anomalous wave tunnelling through a general effective double‐barrier model constructed by dispersion engineering, while preserving mode information. The observed tunnelling mechanism is corroborated well by experimental results in the microwave realm. Specifically, evanescent waves bridge the gap between external space and potential well, allowing us to modulate the leaky modes within the potential well and thus achieve multiple resonant tunnelling. Due to the constant phase difference between adjacent maximum tunnelling, such mechanism broadens the potential of binary integrated devices. For example, assembling the tunnelling unit into arrays straightforwardly alleviates the trade‐off dilemma between diffraction law and cut‐off frequency. In addition, this approach provides an ideal toolbox for achieving multifunctional tunnelling across waveguide modes of various orders or polarizations, which can boost various applications in optical filters, tunneling lasers, optical switching, and sensing. [ABSTRACT FROM AUTHOR]

Ultrafast manipulation of the Néel vector in metallic antiferromagnets most commonly occurs by generation of spin-orbit (SOT) or spin-transfer (STT) torques. Here, we predict another possibility for antiferromagnetic domain switching by using novel laser optical torques (LOTs). We present results of atomistic spin dynamics simulations from the application of LOTs for all-optical switching of the Néel vector in the antiferromagnet Mn2Au. The driving mechanism takes advantage of the sizeable exchange enhancement, characteristic of antiferromagnetic dynamics, allowing for picosecond 90 and 180-degree precessional toggle switching of the Néel vector with laser fluences on the order of mJ/cm2. A special symmetry of these novel torques greatly minimises the over-shooting effect common to precessional spin switching by SOT and STT methods. We demonstrate the opportunity for LOTs to produce deterministic, non-toggle switching of single antiferromagnetic domains. Lastly, we show that even with sizeable ultrafast heating by laser in metallic systems, there exist a large interval of laser parameters where the LOT-assisted toggle and preferential switchings in magnetic grains have probabilities close to one. The proposed protocol could be used on its own for all-optical control of antiferromagnets for computing or memory storage, or in combination with other switching methods to lower energy barriers and/or to prevent over-shooting of the Néel vector. [ABSTRACT FROM AUTHOR]

Optical switching of the electrical operating point of individual crystalline silicon modules has previously been demonstrated as an elegant noncontact method for outdoor photoluminescence image acquisition in full daylight, with the important advantage that no modifications to the system wiring are required. Herein, a modified approach for photoluminescence imaging acquisition in large photovoltaic arrays, enabled by simultaneous optical switching of all modules within a series‐connected string, is demonstrated. This improved method is a simpler approach and allows for significantly increased measurement throughput. Quantitative assessment of image data acquired in full daylight is possible since all modules in a string are series connected and operate at the same current. Excellent agreement is reported for voltage variations between modules that are inferred from daylight photoluminescence image data and measurements conducted under controlled laboratory conditions. [ABSTRACT FROM AUTHOR]

【Objective】In recent years, Artificial Intelligence Generated Content(AIGC)has set off the artificial intelligence revolution. The network connection of the Intelligent Computing Center(ICC)has also developed in the direction of ultra-high bandwidth, intelligent lossless, and computing network convergence. Therefore, the optical network of the ICC needs to reduce the inter-card communication time in order to improve the efficiency of data access.【Methods】The paper addresses the networking architecture of optical networks for ICC scenarios to realize a lossless network with large bandwidth, low latency and high Central Processor Unit (CPU) efficiency, which can satisfy the demand of large model training and reasoning in ICC. This paper analyzes in detail the traffic distribution characteristics of the ICC and the communication flow characteristics under the AI large model training networking scenario. It also conducts in-depth research on the technologies such as Ethernet lossless network based on Remote Direct Memory Access(RDMA) technology and optoelectronic co-encapsulation. Finally it carries out the networking practice and latency test under the ICC scenario.【Results】The RDMA over Converged Ethernet(RoCE)-based transport scheme proposed in this paper has the capabilities of priority-based flow control, displaying congestion notification, enhanced transport selection and data center bridge capability switching protocols, which can realize lossless transmission based on Ethernet protocols in data centers. The test results in this paper show that the transmission delay using the RoCE protocol is approximately stable at around 1 μs and significantly outperforms the Internet Wide Area RDMA Protocol(iWARP).【Conclusion】In this paper, based on the traffic characterization in the intelligent computing scenario, we have studied the key characteristics of the lossless Ethernet network in the ICC, and used the RDMA technology to realize the enhancement of the transmission efficiency of the optical switching network in the scenario of the ICC. We have also put forward a lossless Ethernet network scheme under the large model inference scenario of the ICC, and explored the feasible direction for the application of the RDMA technology in the intelligent computing scenario. The proposed scheme explores a feasible direction for the application of RDMA technology in the smart computing scenario.

With the development of Artificial Intelligence(AI)technologies such as large language models and the promotion of major national projects such as "Naional Somputing Network to Synergize East and West", the internal network interconnection of Artificial Intelligence Data Centers (AIDC) and Computing-Power Networks (CPNs) has become an important tendency of optical network development. Compared with the traditional data-oriented interconnection, the AIDC networks and CPNs have a higher demand for transmission delay, throughput and determinism. On the one hand, high density, low-latency processing and computing resource scheduling are required within the AIDC to meet large-scale real-time training and reasoning. On the other hand, interconnection between the AIDCs requires high-bandwidth, low-latency, high-reliability data transmission and resource sharing to support multi-data-center collaboration and failure recovery. Therefore, the Computing-Power Interconnection (CPI) needs optical switching technology to support efficient data transmission in the optical transport network within the AIDCs and fast bandwidth scheduling between the AIDCs. Hence, constructing a CPI-oriental optical switching network can accommodate the AIDC network requirements and provide efficient, deterministic, and reliable data services. In this paper, we analyze the optical switching technology for AIDC networks, including CPI architecture, data switching and application scenarios.

Synthetic ferrimagnets are an attractive material class for spintronics as they provide access to all-optical switching of magnetization and, at the same time, allow for ultrafast domain wall motion at angular momentum compensation. In this work, we systematically study the effects of strain on the perpendicular magnetic anisotropy and magnetization compensation of Co/Gd and Co/Gd/Co/Gd synthetic ferrimagnets. First, the spin reorientation transition of a bilayer system is investigated in wedge type samples, where we report an increase in the perpendicular magnetic anisotropy in the presence of in-plane strain. Using a model for magnetostatics and spin reorientation transition in this type of system, we confirm that the observed changes in anisotropy field are mainly due to the Co magnetoelastic anisotropy. Second, the magnetization compensation of a quadlayer is studied. We find that magnetization compensation of this synthetic ferrimagnetic system is not altered by external strain. This confirms the resilience of this material system against strain that may be induced during the integration process, making Co/Gd ferrimagnets suitable candidates for spintronics applications. [ABSTRACT FROM AUTHOR]

The utilization of optical directional couplers has emerged as a viable alternative to conventional systems for the execution of error detection using optical signals. The proposed circuit efficiently converts 4-bit binary input signals to gray code representation in the optical domain, reducing errors during transmission and computation. An even/odd parity checker module is also included in the circuit, which improves data integrity and detects single-bit errors in transmitted data. The theoretical basis for the electro-optic effect and its use in directional couplers (EODC) for optical signal transmission inside the proposed circuit. The framework for sophisticated efficient photonic circuit designs with improved error detection and correction capabilities is laid by using EODC, which simplify design and enable seamless integration with existing optical communication technologies. The proposed device layout is made of GaAlAs material produced from a 3 μ m × 3 u m modulator. The coupling length (L C) of the device is set to L C = 1 cm . The EODC performs perfect switching with a light wavelength of 900 nm by creating a refractive index change (Δ n) of approximately Δ n ≅ 1 × 10 - 4 . An electric field magnitude of approximately 3 × 10 4 V / cm is required to achieve this switching, which corresponds to a voltage of 10 V applied across the electrodes of an EODC over a 3 μ m channel. [ABSTRACT FROM AUTHOR]

A hybrid structure composed of a grating coupled graphene structure and two one-dimensional photonic crystals (PhCs) is investigated, where the topological edge state (TES) and the graphene surface plasmon polariton (GSPP) are coupled to generate Fano resonances. The grating coupled graphene structure is used to excite the GSPP and provides a broad resonance. The two PhCs are designed to possess opposite topological properties; thus, the TES appears at the interface and exhibits a narrow resonance. The constructive and destructive interference between the GSPP and the TES results in the Fano resonance. By analyzing the resonant behaviors, it is found that the line shape of Fano resonance can be actively tuned by the graphene Fermi energy. We apply our results to the optical switching, a high-performance optical switch is achieved, and the modulation depth can reach as high as 23.31 dB. In addition, owing to the characteristic of Fano resonance with steep dispersion and asymmetric profile, our designs might offer an alternative strategy to achieve potential applications in sensors, filters, optical switches, and slow-light devices. [ABSTRACT FROM AUTHOR]

We propose a scheme to investigate the spatial modulation of the refractive index in a dense atomic ensemble under the action of the Laguerre–Gaussian (LG) beams. Theoretical derivations based on a density-matrix approach associated with numerical simulations are utilized to study the behaviors of the index of refraction, showing that the azimuthal and radial mode indices (i.e., l 2 and p 2) of the LG beams significantly affect the real and imaginary parts of the refractive index. To be specific, the number of the dispersive peaks is determined by (p 2 + 1) | l 2 | , and there are 2 | l 2 | lossless petals in conjunction with p 2 concentric absorption rings centered on the vortex center. Furthermore, by tuning the phase values of the electric and magnetic components of the electromagnetic field, the index of refraction can be drastically tuned from negative to zero to positive and accompanied by periodic absorption and amplification. This investigation provides a powerful tool for manipulating the index of refraction through a nonlinear interaction between atoms and the vortex beams and suggests potential applications in optical switching, logic gates, and optical storage with spatially varying refractive indices. [ABSTRACT FROM AUTHOR]

2D van der Waals (vdW) layered materials exhibit significant exciton binding energy and versatile stacking options, making them ideal for room‐temperature exciton‐polariton devices used in low‐threshold lasing, nonlinear optical switching, and quantum computing. However, most existing systems depend on external optical microcavities coupled with single monolayers, leading to limited controllability and increased costs. Here, external cavity‐free vdW magnet CrSBr crystals are presented that feature magnetically controllable self‐hybridized exciton‐polaritons that remain stable up to room temperature. The ultrastrong exciton‐photon coupling suppresses donor‐, phonon‐, and defect‐related emissions. Furthermore, the exciton‐polariton dispersion and emission spectra can be effectively controlled by adjusting the magnetic field, temperature, and CrSBr thickness. This vdW exciton‐polariton material platform, demonstrating remarkable magnetic responsiveness in open cavity configurations under ambient conditions, paves the way for the development of compact, fast, and low‐loss spin, quantum, and magneto‐photonic devices. [ABSTRACT FROM AUTHOR]

Optical switching technology is emerging as a solution to the limitations of traditional electronic switching. Combining optical switching with mode‐division multiplexing effectively overcomes the limitations of expanding switching capacity solely by increasing the number of ports. This paper introduces a compact four‐mode 2 × 2 optical switch and a four‐mode reconfigurable non‐blocking 4 × 4 optical switch matrix based on the Beneš architecture. The multimode 2 × 2 switch achieves an extinction ratio larger than 15 dB for all modes in the wavelength range of 1530–1590 nm. The multimode 4 × 4 switch matrix has an extinction ratio exceeding 9 dB for all modes and states in the C‐band, with a compact size (1.46 × 0.23 mm2) and low power consumption (0–154 mW). It supports high‐integrity 50 Gbaud PAM4 signal transmission with a bit error rate below the forward error correction limit. These devices pave the way for enhanced integration density and capacity in optical switching systems. [ABSTRACT FROM AUTHOR]

We have synthesized an acidic pH‐activatable dual targeting ratiometric fluorescent probe‐peptide conjugate using the SPPS protocol on Rink amide AM resin. Living carcinoma cell specific active targeting, successive cell penetration, and selective staining of lysosomes are accomplished. Real‐time monitoring of lysosomes, 3D, and multicolor cancer cell imaging are also attained. The de novo design consists of the integration of multifunctionality into a single molecular scaffold, e. g., RGDS peptide residue to target cancer cell surface overexpressed receptor αVβ3 integrin, live‐cell penetrating organic unsymmetrical rhodamine‐hemicyanine chromophore comprising a lysosome targeting morpholine group, and an acidic pH openable spiro‐lactam ring for a visible‐to‐NIR switchable ratiometric response. Water‐soluble fluorescent probe‐peptide conjugate exhibits intramolecular spirolactamization at basic pH through Arg amide N. The visible spirolactam state predominantly exists at physiological and basic pH and can be switched to the highly conjugated NIR open amide state (λem=735 nm) through spiro‐lactam ring opening triggered by acidic pH with a huge bathochromic shift (Δλabs=336 nm, ΔλFL=265 nm). Moreover, pH‐sensitive ratiometric optical switching is achieved. This in situ acidic cancer cell lysosome activatable multifunctional fluorophore‐peptide conjugate shows augmented molar absorptivity, enhanced quantum yield, and improved fluorescence lifetime at acidic lysosomal pH; negligible cytotoxicity; and dual targeted ratiometric imaging capability of living cancer cell selective lysosomes with a pKa value of 5.1. [ABSTRACT FROM AUTHOR]

The reverse-mode smart windows, which usually fabricated by polymer stabilized liquid crystal (PSLC), are more practical for scenarios where high transparency is a priority for most of the time. However, the polymer stabilized cholesteric liquid crystal (PSCLC) film exhibits poor spacing stability due to the mobility of CLC molecules during the bending deformation. In this work, a reverse-mode PSCLC flexible film with excellent bending resistance was fabricated by the construction of polymer spacer columns. The effect of the concentration of the polymerizable monomer C6M and chiral dopant R811 on the electro-optical properties and polymer microstructure of the film were studied. The sample B2 containing 3 wt% of C6M and 3 wt% R811 presented the best electro-optical performance. The electrical switch between transparent and opaque state of the flexible PSCLC film after bending not only indicated the excellent electro-optical switching performance, but also demonstrated the outstanding bending resistance of the sample with polymer spacer columns, which makes the PSCLC film containing polymer spacer columns have a great potential to be applied in the field of flexible devices. [ABSTRACT FROM AUTHOR]

The technology of reconfigurable optical networks (RONs) is growing to be a promising solution to effectively cater to the rapidly increasing traffic generated by the digital society. The present study offers an overview of the datacenter technology and optical datacenter with details of its concepts and technologies. First, the optical data center systems are described and the components that describe it are network operations. Then, we detail the specific technologies that are important to data center networks throughout wide-area networks, analyzing them deeply. Finally, we make a comprehensive between some related works with an analysis of the algorithmic challenges faced by these technologies. In addition, we examine the solutions that have been developed to address these challenges and explore the relevant systems and implementation considerations. [ABSTRACT FROM AUTHOR]

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Hyperbolic metamaterials (HMMs) are highly anisotropic materials with the unique property of generating electromagnetic modes. Understanding how these materials can be applied to control the propagation of light waves remains a major focus in photonics. In this study, we inserted a finite-size HMM rod into the point defect of two-dimensional photonic crystals (PhCs) and investigated the unique cavity modes of this hybrid system. The HMM enhances the efficiency of the cavity system in controlling light transmission. Numerical results demonstrate that the cavity modes based on HMMs can be categorized into various types, showing high Q-factors and promising potential for resonant modulation. Furthermore, the switching performance of the cavity with an HMM rod was examined, revealing that the finite-size HMM modes are highly frequency-sensitive and suitable for nonlinear controlled all-optical switching. These switches, characterized by low power consumption and high extinction ratios, are highly suitable for integration into photonic systems. Our investigation on the new type of HMM cavity illustrates that anisotropic materials can be effectively applied in cavity systems to generate highly efficient modes for filtering and switching. [ABSTRACT FROM AUTHOR]

The pursuit of advanced brain‐inspired electronic devices and memory technologies has led to explore novel materials by processing multimodal and multilevel tailored conductive properties as the next generation of semiconductor platforms, due to von Neumann architecture limits. Among such materials, antimony sulfide (Sb2S3) thin films exhibit outstanding optical and electronic properties, and therefore, they are ideal for applications such as thin‐film solar cells and nonvolatile memory systems. This study investigates the conduction modulation and memory functionalities of Sb2S3 thin films deposited via the vapor transport deposition technique. Experimental results indicate that the Ag/Sb2S3/Pt device possesses properties suitable for memory applications, including low operational voltages, robust endurance, and reliable switching behavior. Further, the reproducibility and stability of these properties across different device batches validate the reliability of these devices for practical implementation. Moreover, Sb2S3‐based memristors exhibit artificial neuroplasticity with prolonged stability, promising considerable advancements in neuromorphic computing. Leveraging the photosensitivity of Sb2S3 enables the Ag/Sb2S3/Pt device to exhibit significant low operating potential and conductivity modulation under optical stimulation for memory applications. This research highlights the potential applications of Sb2S3 in future memory devices and optoelectronics and in shaping electronics with versatility. [ABSTRACT FROM AUTHOR]

Nowadays, metamaterial absorbers still suffer from limited bandwidth, poor bandwidth scalability, and insufficient modulation depth. In order to solve this series of problems, we propose a metamaterial absorber based on graphene, VO2, gallium silver sulfide, and gold-silver alloy composites with dual-control modulation of temperature and electric field. Then we further investigate the optical switching performance of this absorber in this work. Our proposed metamaterial absorber has the advantages of broad absorption bandwidth, sufficient modulation depth, and good bandwidth scalability all together. Unlike the single inspired layer of previous designs, we innovatively adopted a multi-layer excitation structure, which can realize the purpose of absorption and bandwidth width regulation by a variety of means. Combined with the finite element analysis method, our proposed metamaterial absorber has excellent bandwidth scalability, which can be tuned from 2.7 THz bandwidth to 12.1 THz bandwidth by external electrothermal excitation. Meanwhile, the metamaterial absorber can also dynamically modulate the absorption from 3.8% to 99.8% at a wide incidence angle over the entire range of polarization angles, suggesting important potential applications in the field of optical switching in the terahertz range. [ABSTRACT FROM AUTHOR]

AbstractPresent investigation covers the dielectric and electro-optical study of nematic liquid crystal (NLC) 1823 A dispersed with the ferromagnetic nanoparticles (FNPs) Fe3O4. Three concentrations of nanoparticles (NPs) in the NLC matrix namely 0.1 wt/wt%, 0.3 wt/wt%, and 0.5 wt/wt% are prepared and perceptible changes in the various properties are compared with the pure NLC. Variation of dielectric permittivity (εꓕ) with the variation of frequency and variation of temperature is studied. Dielectric permittivity (εꓕ) is just found to be decreased as we increased the concentration of NPs, which shows that the applied electric field is less impactful on the prepared composites. It is also found that the dielectric permittivity (εꓕ) is increased with the increase of temperature. Birefringence is found to be decreased with the increase in the concentration of the NPs which showed that the orientational order of NLC 1823 A is got to be disturbed due to the presence of the NPs. It is also shown that as the temperature is increased, birefringence is found to get decreased due to its approach toward isotropic phase. Threshold voltage is found to be decreased by 56.25% for the 0.3 wt/wt% and by 25% for 0.1 wt/wt% composite which are pretty good result in context of achieving the low power optical switching devices. The results achieved are tried to be explained on account of the interaction between NLC and NPs. [ABSTRACT FROM AUTHOR]

The construction of mechanically responsive materials with reversible shape‐shifting, shape‐locking, and stretchability holds promise for a wide range of applications in fields such as soft robotics and flexible electronics. Here, we report novel thermoelastic one‐dimensional organic–inorganic hybrids (R/S‐Hmpy)PbI3 (Hmpy=2‐hydroxymethyl‐pyrrolidinium) to show mechanical responses. The single crystals undergo two phase transitions at 310 K and 380 K. When heated to 380 K, they show shape‐shifting and expansion along the b‐axis by about 13.4 %, corresponding to a larger deformation than that of thermally activated shape memory alloys (8.5 %), and exhibit a strong actuation force. During the cooling process, the stretched crystal shape maintains and a shape‐locking phenomenon occurs, which is lifted when the temperature decreases to 305 K. Meanwhile, due to the introduction of chiral ions, the thermal switching shows a 10‐fold second‐order nonlinear switching contrast (common values typically below 3‐fold). This study presents a thermoelastic actuator based on shape‐shifting and ‐locking of organic–inorganic hybrids for the first time. The dielectric and nonlinear optical switching properties of organic–inorganic hybrids broaden the range of applications of mechanically responsive crystals. [ABSTRACT FROM AUTHOR]

Nonlinear optics (NLO) and its applications have attracted increasing research interest in recent years owing to their contribution to the development of photonic technology. Accordingly, in this study, we investigated the NLO response of pumpkin seed oil using the spatial self-phase modulation (SSPM) method. Significant NLO characteristics have been experimentally studied at 405 nm and 532 nm continuous wave (CW) laser wavelengths, yielding second-order nonlinear refractive index ( n 2 , t h ) values of 6.54 × 10 - 5 cm 2 / W and 2.73 × 10 - 5 cm 2 / W , respectively. The findings suggest that the absorption of the material leads to higher optical nonlinearity at shorter wavelengths owing to higher thermal effects. Furthermore, we implemented a light-controlled-light system based on the spatial cross-phase modulation (SXPM) technique employing pumpkin seed oil. We successfully achieved all-optical switching by designing the 'ON' and 'OFF' modes. The results of this study can be considered for the future development of NLO applications. Moreover, our work investigates the potential of pumpkin seed oil for designing low-cost and high-efficiency NLO devices, and this contribution opens up a novel practical avenue for oil-based optical devices. [ABSTRACT FROM AUTHOR]

We investigate the linear interference of a plane wave with different localized waves using the coupled Fokas–Lenells equation (FLE) with four-wave mixing term. We obtain the localized wave solution of the coupled FLE by linear superposition of two distinctly independent wave solutions, namely, the plane wave and one soliton solution and the plane wave and two soliton solution. We obtain several nonlinear profiles depending on the relative phase induced by soliton parameters. We present a systematic analysis of the linear interference profile under four different conditions on the spatial and temporal phase coefficients of interfering waves. We further investigate the interaction of two soliton solution and a plane wave. In this case, we find that, asymptotically, two soliton profiles may be similar or different from each other depending on the choices of soliton parameters in the two cases. The present analysis may also be applied to study the linear interference pattern of other localized waves. We believe that the results obtained by us shall be useful in soliton control, all-optical switching, and optical computing. [ABSTRACT FROM AUTHOR]

Based on the unique insulator-metal phase transition property of vanadium dioxide (VO2), we propose an integrated metasurface with a switchable mechanism between ultra-broadband absorption and polarization conversion, operating in the terahertz (THz) frequency range. The designed metasurface device is constructed using a stacked structure composed of VO2 quadruple rings, a dielectric layer, copper stripes, VO2 film, a dielectric layer, and a copper reflection layer. Our numerical simulations demonstrate that our proposed design, at high temperatures (above 358 K), exhibits an ultra-broadband absorption ranging from 4.95 to 18.39 THz, maintaining an absorptivity greater than 90%, and achieves a relative absorption bandwidth of up to 115%, significantly exceeding previous research records. At room temperature (298 K), leveraging VO2's insulating state, our proposed structure transitions into an effective polarization converter, without any alteration to its geometry. It enables efficient conversion between orthogonal linear polarizations across 3.51 to 10.26 THz, with cross-polarized reflection exceeding 90% and a polarization conversion ratio over 97%. More importantly, its relative bandwidth reaches up to 98%. These features highlight its wide-angle, extensive bandwidth, and high-efficiency advantages for both switching functionalities. Such an ultra-broadband convertible design offers potential applications in optical switching, temperature dependent optical sensors, and other tunable THz devices in various fields. [ABSTRACT FROM AUTHOR]

We explore novel optomechanically induced transparency (OMIT) and prolonged slow light in a linear and quadratic optomechanical system (OMS) with the Coulomb coupling. The hybrid OMS includes a Fabry–Pérot cavity and two charged mechanical resonators (MR1 inside the cavity and MR2 outside the cavity), where the interaction between the charged MR1 and the cavity field are both linear and quadratic in the MR1's displacement, and the charged MR1 and the charged MR2 mutually coupled via Coulomb interaction. Specifically, the transmission of the output field exhibits three transparency window dips. The Coulomb coupling strength is responsible for creating two transparency window dips near δ / ω m = 1 , which results from the mechanical dressed mode. Simultaneously, the quadratic coupling between the charged MR1 and the optical cavity field significantly contributes to another transparency window dip near δ / ω m = 2 , which is attributed to the two-phonon process. In addition, by adjusting the value of Coulomb coupling strength, linear (quadratic) coupling and frequency of the two mechanical resonators, one can attain prolonged slow light with a group delay extending to tens of milliseconds. Furthermore, the positive (negative) value of quadratic coupling strength can determine the switching behavior of the group delay (i.e., from superluminal to subluminal propagation) on the right (left) side of δ / ω m = 2 . We believe that the results have potential applications in manipulating the performance of OMIT devices and optical switching. [ABSTRACT FROM AUTHOR]

Spectral routing techniques have attracted plenty of research attention for the past decades, as they enable light manipulation in both the frequency domain and the spatial domain, which is crucial for applications in on-chip spectroscopy, optical switching, and modern communications. Here, we demonstrate an ultra-compact asymmetric nanoplasmonic router for communication bands that routes O and C bands to opposite positions. The nanorouter consists of two uneven grooves that create bidirectional scattered optical fields, utilizing the interference between different optical modes inside the grooves. A broadband spectrum exceeding 100 nm and a maximum extinction ratio of 31 dB are achieved, providing new opportunities for nanophotonic color routing solutions and extensions to other areas such as imaging sensors and spectral measurements. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dynamical manipulation of plasmon-induced transparency (PIT) in graphene metasurfaces is promising for optoelectronic devices such as optical switching and modulating; however, previous design approaches are limited within one or two bright/dark modes, and the realization of dual PIT windows through triple bright modes in graphene metasurfaces is seldom mentioned. Here, we demonstrate that dual PIT can be realized through a symmetry-engineered graphene metasurface, which consists of the graphene central cross (GCC) and graphene rectangular ring (GRR) arrays. The GCC supports a bright mode from electric dipole (ED), the GRR supports two nondegenerate bright modes from ED and electric quadrupole (EQ) due to the C2v symmetry breaking, and the resonant coupling of these three bright modes induces the dual PIT windows. A triple coupled-oscillator model (TCM) is proposed to evaluate the transmission performances of the dual PIT phenomenon, and the results are in good agreement with the finite-difference time-domain (FDTD) method. In addition, the dual PIT windows are robust to the variation of the structural parameters of the graphene metasurface except for the y-directioned length of the GRR. By changing the carrier mobility of graphene, the amplitudes of the two PIT windows can be effectively tuned. The alteration of the Fermi level of graphene enables the dynamic modulation of the dual PIT with good performances for both modulation degree (MD) and insertion loss (IL). [ABSTRACT FROM AUTHOR]

In the literature, three-stage switching networks have been considered for nodes in elastic optical networks, where switches with spectrum conversion capability are placed in the first and third stages (wavelength–space–wavelength—WSW) or only in the second stage (space–wavelength–space—SWS). This paper proposes three-stage switching networks where the switches with spectrum conversion functions are located only in the first stage (wavelength–space–space—WSS) or only in the third stage (space–space–wavelength—SSW). For these networks, the strict-sense non-blocking conditions are derived and proved, and the number of elements required for their construction is assessed. It turns out that the proposed networks can be constructed with 50% fewer tunable spectrum converters than in the WSW networks, and this reduction is even greater in the case of the SWS networks. [ABSTRACT FROM AUTHOR]

A phase shift gate deals with the change in phase of light signals passing through it. In this paper, authors propose the tristate form of the phase shift gate and its implementation using frequency and phase encoding techniques simultaneously. Tristate system is capable to process more information simultaneously than that of a two-state system. Three different gate matrices are obtained for the phase shift gate operation. Then, the equivalent quantum optical circuits are developed corresponding to those gate matrices. The optical switching operation is established by using electro-optic Pockels material. One of the tristate phase shift gates is designed on a photonic crystal layout with a footprint area of 189 µm2 to achieve a better response time and higher bit rate of the operation. The circuit operation is simulated by FDTD method to check the operation of the circuit. The response time of the system is obtained to be 0.283 picoseconds. [ABSTRACT FROM AUTHOR]

Magnetic tunnel junctions (MTJs) are elementary units of magnetic memory devices. For high-speed and low-power data storage and processing applications, fast reversal of the magnetization by an ultrashort laser pulse is extremely important. We demonstrate single-shot switching of Tb/Co-multilayer based nanoscale MTJs by combining the optical writing and the electrical read-out methods. A 90-fs-long laser pulse switches the magnetization of the storage layer (SL). The change in the tunneling magnetoresistance (TMR) between the SL and a reference layer (RL) is probed electrically across the oxide barrier. Single-shot switching is demonstrated by varying the cell diameter from 300 nm to 20 nm. The anisotropy, magnetostatic coupling, and switching probability exhibit cell-size dependence. By suitable association of laser fluence and magnetic field, successive commutation between high-resistance and low-resistance states is achieved. The nature of the magnetization reversal of both SL and RL in a continuous film is probed with a depth-resolved magneto-optical Kerr effect (MOKE) magnetometry. The ultrafast dynamics in the continuous full-MTJ stack is investigated with the time-resolved pump–probe technique. Our experimental findings provide strong support for the growing interest in ultrafast spintronic devices.