Contents
2021
Volume: 19 Issue 10
17 Article(s)

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Research Articles
Atmospheric, Oceanic, Space, and Environmental Optics
Reconstitution of optical orbital angular momentum through strongly scattering media via feedback-based wavefront shaping method
Lanting Li, Yuanlin Zheng, Haigang Liu, and Xianfeng Chen
Chinese Optics Letters
  • Publication Date: Aug. 20, 2021
  • Vol.19 Issue, 10 100101 (2021)
Diffraction, Gratings, and Holography
Dual-band independent phase control based on high efficiency metasurface [Invited]
Jinxing Li, Yueyi Yuan, Qun Wu, Shah Nawaz Burokur, and Kuang Zhang
A general method to realize arbitrary dual-band independent phase control is proposed and demonstrated in this paper. A double-layered C-shape reflective meta-atom is designed to realize independent phase control with high efficiency. As a proof of concept, we propose two functional metasurfaces in the microwave region; the first metasurface performs beam steering in different directions, and the second metasurface generates achromatic beam steering at two distinct frequencies. Both simulation and measurement results agree well with the theoretical pre-setting. The maximum measured efficiency is 88.7% and 92.3% at 6.8 GHz and 8.0 GHz, respectively, for one metasurface, and 91.0% and 89.8% at 6.9 GHz and 8.6 GHz, respectively, for the other.
Chinese Optics Letters
  • Publication Date: Aug. 23, 2021
  • Vol.19 Issue, 10 100501 (2021)
Imaging Systems and Image Processing
Computational ghost imaging with compressed sensing based on a convolutional neural network
Hao Zhang, and Deyang Duan
Computational ghost imaging (CGI) has recently been intensively studied as an indirect imaging technique. However, the image quality of CGI cannot meet the requirements of practical applications. Here, we propose a novel CGI scheme to significantly improve the imaging quality. In our scenario, the conventional CGI data processing algorithm is optimized to a new compressed sensing (CS) algorithm based on a convolutional neural network (CNN). CS is used to process the data collected by a conventional CGI device. Then, the processed data are trained by a CNN to reconstruct the image. The experimental results show that our scheme can produce higher quality images with the same sampling than conventional CGI. Moreover, detailed comparisons between the images reconstructed using the deep learning approach and with conventional CS show that our method outperforms the conventional approach and achieves a ghost image with higher image quality.
Chinese Optics Letters
  • Publication Date: Aug. 16, 2021
  • Vol.19 Issue, 10 101101 (2021)
Instrumentation, Measurement, and Optical Sensing
Generic nonlinear error compensation algorithm for phase measuring profilometry
Xin Yu, Shanshan Lai, Yuankun Liu, Wenjing Chen, Junpeng Xue, and Qican Zhang
Chinese Optics Letters
  • Publication Date: Aug. 16, 2021
  • Vol.19 Issue, 10 101201 (2021)
Broadband instantaneous multi-frequency measurement based on chirped pulse compression
Beibei Zhu, Min Xue, Changyuan Yu, and Shilong Pan
A broadband instantaneous multi-frequency measurement system based on chirped pulse compression, which potentially has a sub-megahertz (MHz) accuracy and a hundred-gigahertz (GHz) measurement range, is demonstrated. A signal-under-test (SUT) is converted into a carrier-suppressed double-sideband (CS-DSB) signal, which is then combined with an optical linearly frequency-modulated signal having the sweeping range covering the +1st-order sideband of the CS-DSB signal. With photodetection, low-pass filtering, and pulse compression, accurate frequencies of the SUT are obtained via locating the correlation peaks. In the experiment, single- and multi-frequency measurements with a measurement range from 3 to 18 GHz and a measurement accuracy of <±100 MHz are achieved.
Chinese Optics Letters
  • Publication Date: Aug. 23, 2021
  • Vol.19 Issue, 10 101202 (2021)
Integrated Optics
Human-like stereo sensors using plasmonic antenna embedded MZI with space–time modulation control [Invited] | Editors' Pick
A. Garhwal, A. E. Arumona, P. Youplao, K. Ray, I. S. Amiri, and P. Yupapin
Chinese Optics Letters
  • Publication Date: Aug. 20, 2021
  • Vol.19 Issue, 10 101301 (2021)
Silicon non-blocking 4 × 4 optical switch with automated polarization adjustment
Xiaorui Li, Liangjun Lu, Wei Gao, Xin Li, Jianping Chen, and Linjie Zhou
We demonstrate a polarization-insensitive silicon 4×4 optical switch based on Mach–Zehnder interferometer (MZI) switch elements. On-chip polarization controllers are integrated before the switch fabric to automatically adjust an arbitrary input polarization to the transverse electric mode. The 4×4 switch fabric is based on a dilated double-layer network architecture to completely cancel the first-order crosstalk. Thermo-optic phase shifters are integrated in the MZI switch elements and the polarization controllers for adjustment of the switching state and polarization, respectively. We develop a polarization control algorithm based on a gradient descent method for automated polarization control. The polarization recovery time is less than 4 ms, and the measured polarization-dependent loss is ∼2 dB. The scheme provides a new solution for realizing polarization-insensitive silicon optical switches.
Chinese Optics Letters
  • Publication Date: Aug. 13, 2021
  • Vol.19 Issue, 10 101302 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Narrow vertical beam divergence angle for display applications of 645 nm lasers
Yufei Jia, Yufei Wang, Xuyan Zhou, Linhai Xu, Pijie Ma, Jingxuan Chen, Hongwei Qu, and Wanhua Zheng
Chinese Optics Letters
  • Publication Date: Oct. 18, 2021
  • Vol.19 Issue, 10 101401 (2021)
Micro displacement reconstruction of self-mixing grating interferometer based on Littrow structure
Xiufang Wang, Lina Feng, Peng Chen, Zhen Huang, and Ye Yuan
Chinese Optics Letters
  • Publication Date: Aug. 12, 2021
  • Vol.19 Issue, 10 101402 (2021)
Light-matter Interaction
Perfect light absorption in monolayer MoS2 empowered by optical Tamm states
Yangwu Li, Hua Lu, Jiadeng Zheng, Shichang Li, Xiao Xuan, and Jianlin Zhao
Chinese Optics Letters
  • Publication Date: Aug. 20, 2021
  • Vol.19 Issue, 10 103801 (2021)
Microwave Photonics
Photonic-assisted FSK signal generation based on carrier phase-shifted double sideband modulation
Muguang Wang, Yu Tang, Jian Sun, Jing Zhang, Qi Ding, Beilei Wu, and Fengping Yan
Chinese Optics Letters
  • Publication Date: Aug. 23, 2021
  • Vol.19 Issue, 10 103901 (2021)
Optical Design and Fabrication
Multi-focused droplet lens array inspired by movable-type printing technology
Bo Dai, Zhengmeng Zhou, Yan Long, Mingliang Pan, Zeyuan Song, and Dawei Zhang
Chinese Optics Letters
  • Publication Date: Jul. 23, 2021
  • Vol.19 Issue, 10 102201 (2021)
Physical Optics
Dual-frequency fringe for improving measurement accuracy of three-dimensional shape measurement
Zixiao Miao, and Qican Zhang
A new phase unwrapping method based on dual-frequency fringe is proposed to improve both high accuracy and large measurement range of three-dimensional shape measurement by synthesizing the projected dual-frequency fringes obtaining higher and lower frequencies. The lower-frequency one is their phase difference, which can help unwrap the wrapped phase of the higher-frequency one from their phase sum. In addition, the relationship between the measuring accuracy and the frequencies of the projected fringes is studied to guide the frequency selection in actual measurement. It is found that the closer the two frequencies are, the higher the measurement accuracy will be. The computer simulation and experiment results show the viability of this method.
Chinese Optics Letters
  • Publication Date: Aug. 12, 2021
  • Vol.19 Issue, 10 102601 (2021)
Spectroscopy
Identifying self-trapped excitons in 2D perovskites by Raman spectroscopy [Invited] | Editors' Pick
Junze Li, Junchao Hu, Jiaqi Ma, Xinglin Wen, and Dehui Li
Two-dimensional (2D) perovskites exhibit broadband emission due to strong exciton–phonon coupling-induced self-trapped excitons and thus would find important applications in the field of white-light emitting devices. However, the available identifying methods for self-trapped excitons are currently rather limited and complex. Here, we identify the existence of self-trapped excitons by Raman spectroscopy in both excited and non-excited states. Under excited states, the shifting of the Raman peak indicates the presence of the lattice distortion, which together with the extra Raman scattering peak reveals the presence of self-trapped excitons. Our work provides an alternative simple method to study self-trapped excitons in 2D perovskites.
Chinese Optics Letters
  • Publication Date: Jul. 23, 2021
  • Vol.19 Issue, 10 103001 (2021)
Ultrafast Optics and Attosecond/High-field Physics
Polarization dependent clamping intensity inside a femtosecond filament in air
Hao Guo, Xiang Dong, Tie-Jun Wang, Xuan Zhang, Na Chen, Fukang Yin, Yihai Wang, Lingang Zhang, Haiyi Sun, Jun Liu, Jiansheng Liu, Baifei Shen, Olga Kosareva, Yuxin Leng, and Ruxin Li
Laser polarization and its intensity inside a filament core play an important role in filament-based applications. However, polarization dependent clamping intensity inside filaments has been overlooked to interpret the polarization-related filamentation phenomena. Here, we report on experimental and numerical investigations of polarization dependent clamping intensity inside a femtosecond filament in air. By adjusting the initial polarization from linear to circular, the clamping intensity is increased by 1.36 times when using a 30 cm focal length lens for filamentation. The results indicate that clamping intensity inside the filament is sensitive to laser polarization, which has to be considered to fully understand polarization-related phenomena.
Chinese Optics Letters
  • Publication Date: Aug. 12, 2021
  • Vol.19 Issue, 10 103201 (2021)
Reviews
Optical Design and Fabrication
Overview of refractive index sensors comprising photonic crystal fibers based on the surface plasmon resonance effect [Invited] | On the Cover
Chao Liu, Jingwei Lü, Wei Liu, Famei Wang, and Paul K. Chu
Optical fibers have been widely applied to telecommunication, imaging, lasers, and sensing. Among the different types of fibers, photonic crystal fibers (PCFs), also called microstructured optical fibers, characterized by air holes arranged along the length of fibers have experienced tremendous advance due to their unique advantages. They are regarded as a desirable platform to excite surface plasmon resonance (SPR) because of easy realization of phase matching conditions between the fundamental core mode and the plasmonic mode, which plays a critical role in miniaturization and integration of SPR sensors. In this mini-review, the current status of PCF sensors based on SPR is summarized. The theory of SPR is discussed, and simulation methods for PCF-SPR sensors are described. The important parameters including the refractive index detection range, resonance wavelength, and spectral sensitivity responsible for the sensing properties of PCF-SPR sensors are reviewed. The fabrication and the comparison of performances are also illustrated, and, finally, the challenges and future perspectives are outlined.
Chinese Optics Letters
  • Publication Date: Sep. 02, 2021
  • Vol.19 Issue, 10 102202 (2021)

About the Cover

Here is the caption of the cover image: Surface plasmon resonance (SPR) sensor that consists of a D-shaped photonic crystal fiber with plasmonic coatings. The structure is a desirable platform to excite SPR because of easy realization of phase matching.