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A review of complex vector light fields and their applications
摘要： Vector beams, and in particular vector vortex beams, have found many applications in recent times, both as classical fields and as quantum states. While much attention has focused on the creation and detection of scalar optical fields, it is only recently that vector beams have found their place in the modern laboratory. In this review, we outline the fundamental concepts of vector beams, summarise the various approaches to control them in the laboratory, and give a concise overview of the many applications they have spurned.
关键词： hyper-entanglement,vector beams,vector vortex modes,hybrid entanglement,polarisation,spatial light modulators,geometric phase
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - 20-Gb/s Silicon Optical Modulators for the 2 μm Wavelength Band
摘要： We demonstrate silicon-on-insulator based high speed modulators working at a wavelength of 1950 nm. The carrier-depletion Mach-Zehnder interferometer modulator operates at a data rate of 20 Gbit/s with an extinction ratio of 5.8 dB and modulation efficiency (VπLπ) of 2.68 Vcm at 4 V reverse bias.
关键词： high speed modulators,1950 nm,carrier-depletion,silicon-on-insulator,Mach-Zehnder interferometer
更新于2025-09-10 09:29:36
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Microwave Photonic Link With Improved Dynamic Range Through π phase Shift of the Optical Carrier Band
摘要： A microwave photonic link (MPL) with an improved spurious-free dynamic range (SFDR) by introducing a π phase shift to the spectral complements in the optical carrier band (OCB) is proposed and experimentally demonstrated. The fundamental concept to improve the SFDR is to suppress the third-order intermodulation distortion (IMD3) terms while retaining a high gain for the fundamental terms, which is achieved by introducing a π phase shift to the OCB with the joint use of an electrical 90? hybrid coupler and a dual-parallel Mach-Zehnder modulator (DP-MZM). When detecting the optical signal from the DP-MZM at a photodetector (PD), the IMD3 components originated from the beating between different optical sidebands can be fully cancelled, while the gain for the fundamental terms remains reasonably high. Therefore, the SFDR of the MPL is significantly increased. The proposed MPL is experimentally demonstrated. An SFDR of 108.1 dB?Hz2/3 or 120.4 dB?Hz2/3 for a noise floor of -146.9 or -163.9 dBm/Hz is achieved, which is 14 dB or 15 dB higher than that of a conventional intensity-modulation direct-detection (IMDD) MPL.
关键词： parallel intensity modulators,third-order intermodulation,microwave photonic link (MPL),Spurious-free dynamic range (SFDR)
更新于2025-09-10 09:29:36
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Graphene mechanical pixels for Interferometric Modulator Displays
摘要： Electro-optic modulators based on micro-electromechanical systems have found success as elements for optical projectors, for simplified optical spectrometers, and as reflective-type screens that make use of light interference (Interferometric Modulator Display technology). The latter concept offers an exciting avenue for graphene nanomechanical structures to replace classical micro-electromechanical devices and bring about enhancement in performance, especially switching speed and voltage. In this work we study the optical response of electrically actuated graphene drumheads by means of spectrometric and stroboscopic experiments. The color reproducibility and speed of these membranes in producing the desired electro-optic modulation makes them suitable as pixels for high refresh rate displays. As a proof of concept, we demonstrate a Graphene Interferometric Modulator Display prototype with 5 μm-in-diameter pixels that compose a high resolution image (2500 pixels per inch)—equivalent to a 5″ display of 12K—whose color can be changed at frame rates of at least 400 Hz.
关键词： high refresh rate displays,electro-optic modulators,Interferometric Modulator Display,micro-electromechanical systems,graphene
更新于2025-09-10 09:29:36
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Photonic Discrete-time Quantum Walks and Applications
摘要： We present a review of photonic implementations of discrete-time quantum walks (DTQW) in the spatial and temporal domains, based on spatial- and time-multiplexing techniques, respectively. Additionally, we propose a detailed novel scheme for photonic DTQW, using transverse spatial modes of single photons and programmable spatial light modulators (SLM) to manipulate them. Unlike all previous mode-multiplexed implementations, this scheme enables simulation of an arbitrary step of the walker, only limited, in principle, by the SLM resolution. We discuss current applications of such photonic DTQW architectures in quantum simulation of topological effects and the use of non-local coin operations based on two-photon hybrid entanglement.
关键词： time-multiplexing,quantum walks,spatial-multiplexing,spatial light modulators
更新于2025-09-10 09:29:36
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Electrically programmable multi-purpose nonvolatile metasurface based on phase change materials
摘要： We propose an electrically programmable nonvolatile metasurface working at near-IR frequency (λ=1550 nm) based on ITO/Ge2Sb2Te5-ITO/Au crossbar structure. The proposed metasurface can dynamically change its optical function by modulating the crystallization level of Ge2Sb2Te5, which is a phase change material, at each pixel position individually by controlled electrical pulses. We design and optimize the metasurface by using finite-difference time-domain simulations and numerically demonstrate various optical functions including beam steering devices, flat lenses, optical vortex generators, and metasurface holograms with a single device geometry.
关键词： metasurfaces,phase change materials,spatial light modulators,reconfigurable metasurfaces,programmable metasurfaces
更新于2025-09-10 09:29:36
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Electric-field modulation of linear dichroism and Faraday rotation in few-layer phosphorene
摘要： Electro-optical modulators, which use an electric voltage (or an electric field) to modulate a beam of light, are essential elements in present-day telecommunication devices. Using a self-consistent tight-binding approach combined with the standard Kubo formula, we show that the optical conductivity and the linear dichroism of few-layer phosphorene can be modulated by a perpendicular electric field. We find that the field-induced charge screening plays a significant role in modulating the optical conductivity and the linear dichroism. Distinct absorption peaks are induced in the conductivity spectrum due to the strong quantum confinement along the out-of-plane direction and to the field-induced forbidden-to-allowed transitions. The field modulation of the linear dichroism becomes more pronounced with increasing number of phosphorene layers. We also show that the Faraday rotation is present in few-layer phosphorene even in the absence of an external magnetic field. This optical Hall effect is induced by the reduced lattice symmetry of few-layer phosphorene. The Faraday rotation is greatly influenced by the field-induced charge screening and is strongly dependent on the strength of perpendicular electric field and on the number of phosphorene layers.
关键词： electric field modulation,linear dichroism,optical conductivity,Faraday rotation,electro-optical modulators,few-layer phosphorene
更新于2025-09-09 09:28:46
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Terahertz two-pixel imaging based on complementary compressive sensing
摘要： A compact terahertz (THz) imaging system based on complementary compressive sensing has been proposed using two single-pixel detectors. By using a mechanical spatial light modulator, sampling in the transmission and re?ection orientations was achieved simultaneously, which allows imaging with negative mask values. The improvement of THz image quality and anti-noise performance has been veri?ed experimentally compared with the traditional reconstructed image, and is in good agreement with the numerical simulation. The demonstrated imaging system, with the advantages of high imaging quality and strong anti-noise property, opens up possibilities for new applications in the THz region.
关键词： image reconstruction techniques,terahertz imaging,spatial light modulators
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Sources of RF Intermodulation Distortion in Silicon Photonic Modulators
摘要： We present a model of intermodulation distortion (IMD) in RF silicon photonic modulators to highlight mechanisms that limit the device linearity. We compare the SFDR of two MZMs to show a common IMD limitation and indicate methods to improve linearity in silicon photonic RF modulators.
关键词： intermodulation distortion,silicon photonic modulators,SFDR,RF photonic systems,linearity
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Lausanne (2018.7.29-2018.8.2)] 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Energy-Efficient Silicon Photonic Crystal Nanocavity Modulator Driven by Indium Oxide Gate
摘要： We report an ultra-energy-efficient silicon photonic crystal nanocavity modulator driven by a metal-oxide-semiconductor (MOS) capacitor consisting of In2O3/HfO2/p-Si stacked film, which yields an ultra-high tuning efficiency of 250pm/V, a strong modulation strength of 4dB/V by a 0.35μm electrode, and a low energy consumption of 3fJ/bit.
关键词： micro-cavity,photonic crystals,waveguide modulators
更新于2025-09-09 09:28:46