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1 Issue (s), 19 Article (s)
Vol.9, Iss.11—Nov.1, 2021 • pp: 2132-2330 Spec. pp:
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Research ArticlesVol.9, Iss.11-Nov..1,2021
Imaging Systems, Microscopy, and Displays
Ten-mega-pixel snapshot compressive imaging with a hybrid coded apertureZhihong Zhang, Chao Deng, Yang Liu, Xin Yuan, Jinli Suo, and Qionghai Dai
High-resolution images are widely used in our everyday life; however, high-speed video capture is more challenging due to the low frame rate of cameras working at the high-resolution mode. The main bottleneck lies in the low throughput of existing imaging systems. Toward this end, snapshot compressive imaging (SCI) was proposed as a promising solution to improve the throughput of imaging systems by compressive sampling and computational reconstruction. During acquisition, multiple high-speed images are encoded and collapsed to a single measurement. Then, algorithms are employed to retrieve the video frames from the coded snapshot. Recently developed plug-and-play algorithms made the SCI reconstruction possible in large-scale problems. However, the lack of high-resolution encoding systems still precludes SCI’s wide application. Thus, in this paper, we build, to the best of our knowledge, a novel hybrid coded aperture snapshot compressive imaging (HCA-SCI) system by incorporating a dynamic liquid crystal on silicon and a high-resolution lithography mask. We further implement a PnP reconstruction algorithm with cascaded denoisers for high-quality reconstruction. Based on the proposed HCA-SCI system and algorithm, we obtain a 10-mega-pixel SCI system to capture high-speed scenes, leading to a high throughput of 4.6 × 109 voxels per second. Both simulation and real-data experiments verify the feasibility and performance of our proposed HCA-SCI scheme.High-resolution images are widely used in our everyday life; however, high-speed video capture is more challenging due to the low frame rate of cameras working at the high-resolution mode. The main bottleneck lies in the low throughput of existing imaging systems. Toward this end, snapshot compressive imaging (SCI) was proposed as a promising solution to improve the throughput of imaging systems by compressive sampling and computational reconstruction. During acquisition, multiple high-speed images are encoded and collapsed to a single measurement. Then, algorithms are employed to retrieve the video frames from the coded snapshot. Recently developed plug-and-play algorithms made the SCI reconstruction possible in large-scale problems. However, the lack of high-resolution encoding systems still precludes SCI’s wide application. Thus, in this paper, we build, to the best of our knowledge, a novel hybrid coded aperture snapshot compressive imaging (HCA-SCI) system by incorporating a dynamic liquid crystal on silicon and a high-resolution lithography mask. We further implement a PnP reconstruction algorithm with cascaded denoisers for high-quality reconstruction. Based on the proposed HCA-SCI system and algorithm, we obtain a 10-mega-pixel SCI system to capture high-speed scenes, leading to a high throughput of 4.6 × 109 voxels per second. Both simulation and real-data experiments verify the feasibility and performance of our proposed HCA-SCI scheme.
Photonics Research
- Publication Date: Oct. 26, 2021
- Vol.9 Issue, 11 11002277 (2021)
Instrumentation and Measurements
Dispersion engineering and measurement in crystalline microresonators using a fiber ring etalonXiaobao Zhang, Guoping Lin, Tang Sun, Qinghai Song, Guangzong Xiao, and Hui Luo
Dispersion engineering and measurement are significant for nonlinear photonic applications using whispering gallery mode microresonators. Specifically, the Kerr microresonator frequency comb as an important example has attracted a great amount of interest in research fields due to the potential capability of full integration on a chip. A simple and cost-efficient way for dispersion measurements is thereby in high demand for designing such a microcomb device. Here, we report a dispersion measurement approach using a fiber ring etalon reference. The free spectral range of the etalon is first measured through sideband modulation, and the dispersion of the etalon is inferred by binary function fitting during the dispersion measurement. This method is demonstrated on two
Photonics Research
- Publication Date: Oct. 21, 2021
- Vol.9 Issue, 11 11002222 (2021)
Integrated Optics
Polarization-insensitive interferometer based on a hybrid integrated planar light-wave circuitGuo-Wei Zhang, Yu-Yang Ding, Wei Chen, Fang-Xiang Wang, Peng Ye, Guan-Zhong Huang, Shuang Wang, Zhen-Qiang Yin, Jun-Ming An, Guang-Can Guo, and Zheng-Fu Han
Interferometers are essential elements in classical and quantum optical systems. The strictly required stability when extracting the phase of photons is vulnerable to polarization variation and phase shift induced by environment disturbance. Here, we implement polarization-insensitive interferometers by combining silica planar light-wave circuit chips and Faraday rotator mirrors. Two asymmetric interferometers with temperature controllers are connected in series to evaluate the single-photon interference. Average interference visibility over 12 h is above 99%, and the variations are less than 0.5%, even with active random polarization disturbance. The experiment results verify that the hybrid chip is available for high-demand applications like quantum key distribution and entanglement measurement.Interferometers are essential elements in classical and quantum optical systems. The strictly required stability when extracting the phase of photons is vulnerable to polarization variation and phase shift induced by environment disturbance. Here, we implement polarization-insensitive interferometers by combining silica planar light-wave circuit chips and Faraday rotator mirrors. Two asymmetric interferometers with temperature controllers are connected in series to evaluate the single-photon interference. Average interference visibility over 12 h is above 99%, and the variations are less than 0.5%, even with active random polarization disturbance. The experiment results verify that the hybrid chip is available for high-demand applications like quantum key distribution and entanglement measurement.
Photonics Research
- Publication Date: Oct. 06, 2021
- Vol.9 Issue, 11 11002176 (2021)
Integrated Optics
Coherent self-control of free-space optical beams with integrated silicon photonic meshesMaziyar Milanizadeh, Fabio Toso, Giorgio Ferrari, Tigers Jonuzi, David A. B. Miller, Andrea Melloni, and Francesco Morichetti
In technologies operating at light wavelengths for wireless communication, sensor networks, positioning, and ranging, a dynamic coherent control and manipulation of light fields is an enabling element for properly generating and correctly receiving free-space optical (FSO) beams even in the presence of unpredictable objects and turbulence in the light path. In this work, we use a programmable mesh of Mach–Zehnder (MZI) interferometers to automatically control the complex field radiated and captured by an array of optical antennas. The implementation of local feedback control loops in each MZI stage, without global multivariable optimization techniques, enables an unlimited scalability. Several functionalities are demonstrated, including the generation of perfectly shaped beams with nonperfect optical antennas, the imaging of a desired field pattern through an obstacle or a diffusive medium, and the identification of an unknown obstacle inserted in the FSO path. Compared to conventional devices used for the manipulation of FSO beams, such as spatial light modulators, our programmable device can self-configure through automated control strategies and can be integrated with other functionalities implemented onto the same photonic chip.In technologies operating at light wavelengths for wireless communication, sensor networks, positioning, and ranging, a dynamic coherent control and manipulation of light fields is an enabling element for properly generating and correctly receiving free-space optical (FSO) beams even in the presence of unpredictable objects and turbulence in the light path. In this work, we use a programmable mesh of Mach–Zehnder (MZI) interferometers to automatically control the complex field radiated and captured by an array of optical antennas. The implementation of local feedback control loops in each MZI stage, without global multivariable optimization techniques, enables an unlimited scalability. Several functionalities are demonstrated, including the generation of perfectly shaped beams with nonperfect optical antennas, the imaging of a desired field pattern through an obstacle or a diffusive medium, and the identification of an unknown obstacle inserted in the FSO path. Compared to conventional devices used for the manipulation of FSO beams, such as spatial light modulators, our programmable device can self-configure through automated control strategies and can be integrated with other functionalities implemented onto the same photonic chip.
Photonics Research
- Publication Date: Oct. 18, 2021
- Vol.9 Issue, 11 11002196 (2021)
Integrated Optics
Thermally enhanced responsivity in an all-silicon optical power monitor based on defect-mediated absorptionQikai Huang, Hui Yu, Qiang Zhang, Yan Li, Weiwei Chen, Yuehai Wang, and Jianyi Yang
We demonstrate a high responsivity all-silicon in-line optical power monitor by using the thermal effect to enhance the quantum efficiency of defect-mediated absorption at 1550 nm. The doping compensation technique is utilized to increase the density of lattice defects responsible for the sub-bandgap absorption and suppress the detrimental free carrier absorption. The 200-μm-long device presents a propagation loss as low as 2.9 dB/cm. Its responsivity is enhanced from 12.1 mA/W to 112 mA/W at
Photonics Research
- Publication Date: Oct. 21, 2021
- Vol.9 Issue, 11 11002205 (2021)
Nanophotonics and Photonic Crystals
Hybrid photonic-plasmonic cavities based on the nanoparticle-on-a-mirror configurationAngela I. Barreda, Mario Zapata-Herrera, Isabelle M. Palstra, Laura Mercadé, Javier Aizpurua, A. Femius Koenderink, and Alejandro Martínez
Hybrid photonic-plasmonic cavities have emerged as a new platform to increase light–matter interaction capable to enhance the Purcell factor in a singular way not attainable with either photonic or plasmonic cavities separately. In the hybrid cavities proposed so far, the plasmonic element is usually a metallic bow-tie antenna, so the plasmonic gap—defined by lithography—is limited to minimum values of several nanometers. Nanoparticle-on-a-mirror (NPoM) cavities are far superior to achieve the smallest possible mode volumes, as plasmonic gaps smaller than 1 nm can be created. Here, we design a hybrid cavity that combines an NPoM plasmonic cavity and a dielectric-nanobeam photonic crystal cavity operating at transverse-magnetic polarization. The metallic nanoparticle can be placed very close (
Photonics Research
- Publication Date: Oct. 28, 2021
- Vol.9 Issue, 11 11002296 (2021)
Nonlinear Optics
Synchronization in Chang-Long Zhu, Yu-Long Liu, Lan Yang, Yu-Xi Liu, and Jing Zhang
Synchronization has great impacts in various fields such as self-clocking, communication, and neural networks. Here, we present a mechanism of synchronization for two mechanical modes in two coupled optomechanical resonators with a parity-time (
Photonics Research
- Publication Date: Oct. 06, 2021
- Vol.9 Issue, 11 11002152 (2021)
Optical and Photonic Materials
Tuning the luminous properties and optical thermometry of Cs2SnCl6 phosphor microcrystals via Bi and Sb codopingShunfa Gong, Ruirui Wu, Sen Yang, Lifang Wu, Minmin Zhang, Qiuju Han, and Wenzhi Wu
The toxicity and instability of lead halide perovskite seriously limit its commercial application in lighting, although it has high photoluminescence (PL) efficiency and adjustable emission. Here, lead-free bismuth (Bi) and antimony (Sb) codoped
Photonics Research
- Publication Date: Oct. 15, 2021
- Vol.9 Issue, 11 11002182 (2021)
Optical and Photonic Materials
Control of phase, polarization, and amplitude based on geometric phase in a racemic helix arrayChao Wu, Quan Li, Zhihui Zhang, Song Zhao, and Hongqiang Li
The Pancharatnam–Berry geometric phase has attracted great interest due to the elegant phase control strategy via geometric transformation of optical elements. The commonly used geometric phase is associated with circular polarization states. Here, we show that by exploiting the geometric phase associated with the two elliptical eigen-polarization states in a racemic metallic helix array, exotic features including full range phase modulation for linear polarization states, diverse polarization conversion, and full complex amplitude modulation can be obtained with rotation of the helices. As a proof of concept, several devices for implementing polarization conversion, vortex beam generating, and lateral dual focusing are built with a racemic helix array in the microwave regime. The calculated and experimental results validate our proposals, which can stimulate various advanced metadevices.The Pancharatnam–Berry geometric phase has attracted great interest due to the elegant phase control strategy via geometric transformation of optical elements. The commonly used geometric phase is associated with circular polarization states. Here, we show that by exploiting the geometric phase associated with the two elliptical eigen-polarization states in a racemic metallic helix array, exotic features including full range phase modulation for linear polarization states, diverse polarization conversion, and full complex amplitude modulation can be obtained with rotation of the helices. As a proof of concept, several devices for implementing polarization conversion, vortex beam generating, and lateral dual focusing are built with a racemic helix array in the microwave regime. The calculated and experimental results validate our proposals, which can stimulate various advanced metadevices.
Photonics Research
- Publication Date: Oct. 26, 2021
- Vol.9 Issue, 11 11002265 (2021)
Optical Devices
Control of angular dispersion in dielectric gratings for multifunctional wavefront shaping and dynamic polarization conversionYiwu Yuan, Jierong Cheng, Fei Fan, Xianghui Wang, and Shengjiang Chang
Compared with traditional optical elements, metasurfaces have shown unique advantages in multifunctionality encoded in different frequencies, polarization states, and orbital angular momentums. However, the study of metasurfaces with well-controlled functions under different incident angles is still in its infancy. Here we propose a general method to tailor the angular dispersion over the simplest binary dielectric grating in the transmission mode. We demonstrate that the angular response is strongly related to the number of waveguide modes inside the grating, so one can intentionally reduce or enhance the angular dispersion by controlling the number of waveguide modes. Independent phase manipulation over incident angles is experimentally demonstrated by a metalens with angle-dependent focus. The angular dispersion in orthogonal polarization states is further utilized to demonstrate angle-insensitive and angle-multiplexed wave plates. These devices with simple configuration and clear physics offer a general platform to expand the scope of beam manipulation over metasurfaces.Compared with traditional optical elements, metasurfaces have shown unique advantages in multifunctionality encoded in different frequencies, polarization states, and orbital angular momentums. However, the study of metasurfaces with well-controlled functions under different incident angles is still in its infancy. Here we propose a general method to tailor the angular dispersion over the simplest binary dielectric grating in the transmission mode. We demonstrate that the angular response is strongly related to the number of waveguide modes inside the grating, so one can intentionally reduce or enhance the angular dispersion by controlling the number of waveguide modes. Independent phase manipulation over incident angles is experimentally demonstrated by a metalens with angle-dependent focus. The angular dispersion in orthogonal polarization states is further utilized to demonstrate angle-insensitive and angle-multiplexed wave plates. These devices with simple configuration and clear physics offer a general platform to expand the scope of beam manipulation over metasurfaces.
Photonics Research
- Publication Date: Oct. 15, 2021
- Vol.9 Issue, 11 11002190 (2021)
Optical Devices
Enhanced performance of a fast GaAs-based terahertz modulator via surface passivationYulian He, Yuansheng Wang, Qinghui Yang, Huaiwu Zhang, and Qiye Wen
Surface-modified semiconductors show enormous potential for opto-terahertz (THz) spatial modulation due to their enhanced modulation depth (MD) along with their inherent broad bandwidth. Taking full advantage of the surface modification, a performance-enhanced, all-optical, fast switchable THz modulator was achieved here based on the surface-passivated GaAs wafer. With a decreased surface recombination rate and prolonged carrier lifetime induced by passivation, S-passivated GaAs was demonstrated as a viable candidate to enhance THz modulation performance in MD, especially at low photodoping levels. Despite a degraded modulation rate owing to the longer carrier lifetime, this passivated GaAs modulator simultaneously realizes a fast modulation at a 69-MHz speed and as high an MD as
Photonics Research
- Publication Date: Oct. 21, 2021
- Vol.9 Issue, 11 11002230 (2021)
Optical Devices
High-efficiency and large light-receiving area superconducting nanowire single-photon detector integrated with high-contrast gratingChen Wei, Wencong Wang, Dongmei Liu, Min Gu, and Xianqiu Wu
By using a high-contrast grating (HCG, high transmittance
Photonics Research
- Publication Date: Oct. 26, 2021
- Vol.9 Issue, 11 11002253 (2021)
Optoelectronics
Highly stable full-color display device with VLC application potential using semipolar μLEDs and all-inorganic encapsulated perovskite nanocrystalTingzhu Wu, Yue Lin, Yu-Ming Huang, Meng Liu, Konthoujam James Singh, Wansheng Lin, Tingwei Lu, Xi Zheng, Jianyang Zhou, Hao-Chung Kuo, and Zhong Chen
A promising approach for the development of effective full-color displays is to combine blue microLEDs (μLEDs) with color conversion layers. Perovskite nanocrystals (PNCs) are notable for their tolerance to defects and provide excellent photoluminescence quantum yields and high color purity compared to metal chalcogenide quantum dots. The stability of PNCs in ambient conditions and under exposure to blue light can be improved using a
Photonics Research
- Publication Date: Oct. 06, 2021
- Vol.9 Issue, 11 11002132 (2021)
Optoelectronics
Ultrabroadband and multiband infrared/terahertz photodetectors with high sensitivityJiaqi Zhu, He Zhu, Mengjuan Liu, Yao Wang, Hanlun Xu, Nasir Ali, Huiyong Deng, Zhiyong Tan, Juncheng Cao, Ning Dai, and Huizhen Wu
Broadband response is pursued in both infrared (IR) and terahertz (THz) detection technologies, which find their applications in both terrestrial and astronomical realms. Herein, we report an ultrabroadband and multiband IR/THz detector based on blocked-impurity-band detecting principle. The detectors are prepared by implanting phosphorus into germanium (Ge:P), where photoresponses with a P impurity band, a self-interstitial defect band, and a vacancy-P (V-P) pair defect band are realized simultaneously. The response spectra of the detectors show ultrabroad and dual response bands in a range of 3–28 μm (IR band) and 40–165 μm (THz band), respectively. Additionally, a tiny mid-IR (MIR) band within 3–4.2 μm is embedded in the IR band. The THz band arises from the P impurity band, whereas the IR and the MIR bands are ascribed to the two defect bands. At 150 mV and 4.5 K, the peak detectivities of the three bands are obtained as
Photonics Research
- Publication Date: Oct. 06, 2021
- Vol.9 Issue, 11 11002167 (2021)
Physical Optics
Off-axis optical levitation and transverse spinning of metallic microparticlesYansheng Liang, Shaohui Yan, Zhaojun Wang, Baoli Yao, and Ming Lei
Optical manipulation of metallic microparticles remains a significant challenge because of the strong scattering forces arising from the high extinction coefficient of the particles. This paper reports a new mechanism for stable confinement of metallic microparticles using a tightly focused linearly polarized Gaussian beam. Theoretical and experimental results demonstrate that metallic microparticles can be captured off the optical axis in such a beam. Meanwhile, the three-dimensionally confined particles are observed spinning transversely as a response to the asymmetric force field. The off-axis levitation and transverse spinning of metallic microparticles may provide a new way for effective manipulation of metallic microparticles.Optical manipulation of metallic microparticles remains a significant challenge because of the strong scattering forces arising from the high extinction coefficient of the particles. This paper reports a new mechanism for stable confinement of metallic microparticles using a tightly focused linearly polarized Gaussian beam. Theoretical and experimental results demonstrate that metallic microparticles can be captured off the optical axis in such a beam. Meanwhile, the three-dimensionally confined particles are observed spinning transversely as a response to the asymmetric force field. The off-axis levitation and transverse spinning of metallic microparticles may provide a new way for effective manipulation of metallic microparticles.
Photonics Research
- Publication Date: Oct. 06, 2021
- Vol.9 Issue, 11 11002144 (2021)
Physical Optics
Sculpturing spatiotemporal wavepackets with chirped pulsesQian Cao, Jian Chen, Keyin Lu, Chenhao Wan, Andy Chong, and Qiwen Zhan
Pulse shaping has become a powerful tool in generating complicated ultrafast optical waveforms to meet specific application needs. Traditionally, pulse shaping focuses on the temporal waveform synthesis. Recent interests in structuring light in the spatiotemporal domain rely on Fourier analysis. A space-to-time mapping technique allows us to directly imprint complex spatiotemporal modulation through taking advantage of the relationship between frequency and time of chirped pulses. The concept is experimentally verified through the generation of spatiotemporal optical vortex (STOV) and STOV lattice. The power of this method is further demonstrated by STOV polarity reversal, vortex collision, and vortex annihilation. Such a direct mapping technique opens tremendous potential opportunities for sculpturing complex spatiotemporal waveforms.Pulse shaping has become a powerful tool in generating complicated ultrafast optical waveforms to meet specific application needs. Traditionally, pulse shaping focuses on the temporal waveform synthesis. Recent interests in structuring light in the spatiotemporal domain rely on Fourier analysis. A space-to-time mapping technique allows us to directly imprint complex spatiotemporal modulation through taking advantage of the relationship between frequency and time of chirped pulses. The concept is experimentally verified through the generation of spatiotemporal optical vortex (STOV) and STOV lattice. The power of this method is further demonstrated by STOV polarity reversal, vortex collision, and vortex annihilation. Such a direct mapping technique opens tremendous potential opportunities for sculpturing complex spatiotemporal waveforms.
Photonics Research
- Publication Date: Oct. 26, 2021
- Vol.9 Issue, 11 11002261 (2021)
Quantum Optics
Submegahertz spectral width photon pair source based on fused silica microspheresErasto Ortiz-Ricardo, Cesar Bertoni-Ocampo, Mónica Maldonado-Terrón, Arturo Garcia Zurita, Roberto Ramirez-Alarcon, Hector Cruz Ramirez, R. Castro-Beltrán, and Alfred B. U’Ren
High-efficiency submegahertz bandwidth photon pair generators will enable the field of quantum technology to transition from laboratory demonstrations to transformational applications involving information transfer from photons to atoms. While spontaneous parametric processes are able to achieve high-efficiency photon pair generation, the spectral bandwidth tends to be relatively large, as defined by phase-matching constraints. To solve this fundamental limitation, we use an ultrahigh quality factor (
Photonics Research
- Publication Date: Oct. 21, 2021
- Vol.9 Issue, 11 11002237 (2021)
Quantum Optics
Adiabaticity in state preparation for spin squeezing of large atom ensemblesShenchao Jin, Han Bao, Junlei Duan, Xingda Lu, Mingfeng Wang, Kai-Feng Zhao, Heng Shen, and Yanhong Xiao
Spin-squeezed state is a many-body entangled state of great interest for precision measurements. Although the absolute sensitivity at the standard quantum limit is better for a larger atom number, the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing. Here, we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression, which is the prerequisite for spin squeezing. This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrology applications.Spin-squeezed state is a many-body entangled state of great interest for precision measurements. Although the absolute sensitivity at the standard quantum limit is better for a larger atom number, the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing. Here, we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression, which is the prerequisite for spin squeezing. This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrology applications.
Photonics Research
- Publication Date: Oct. 28, 2021
- Vol.9 Issue, 11 11002318 (2021)
Silicon Photonics
Ultrawide-band silicon microring avalanche photodiode with linear photocurrent-wavelength responseYang Ren, and Vien Van
We report a CMOS-compatible silicon microring-enhanced avalanche photodiode based on linear defect-state absorption in a
Photonics Research
- Publication Date: Oct. 28, 2021
- Vol.9 Issue, 11 11002325 (2021)
Next-generation Silicon Photonics (2021)
Submission Open:1 July 2021; Submission Deadline: 30 September 2021
Editor (s):
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