Contents 3 Issue (s), 50 Article (s)

Vol.19, Iss.12—Dec.1, 2021 • pp: 120201- Spec. pp:

Vol.19, Iss.11—Nov.1, 2021 • pp: 110601- Spec. pp:

Vol.19, Iss.10—Oct.1, 2021 • pp: 100101- Spec. pp:

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Research ArticlesVol.19, Iss.12-Dec..1,2021
Atomic and Molecular Optics
Uncertainty evaluation of the second-order Zeeman shift of a transportable 87Rb atomic fountain clock
Henan Cheng, Siminda Deng, Zhen Zhang, Jingfeng Xiang, Jingwei Ji, Wei Ren, Tang Li, Qiuzhi Qu, Liang Liu, and Desheng Lü
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 120201 (2021)
Biophotonics
Recognizing local artifacts in two-photon imaging of dendrites beneath blood vessels in vivo
Cheng Jin, Ruheng Shi, Chi Liu, and Lingjie Kong
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121701 (2021)
Imaging Systems and Image Processing
Fine edge detection in single-pixel imaging
Liyu Zhou, Xianwei Huang, Qin Fu, Xuanpengfan Zou, Yanfeng Bai, and Xiquan Fu
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121101 (2021)
Infrared and Terahertz Photonics
Continuous-wave terahertz diffraction tomography for measuring three-dimensional refractive index maps
Dayong Wang, Xiaoyu Jin, Jie Zhao, Yunxin Wang, Lu Rong, and John J. Healy
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123701 (2021)
Integrated Optics
High-performance ultra-compact polarization splitter-rotators based on dual-etching and tapered asymmetrical directional coupler
Changjian Xie, Xihua Zou, Fang Zou, and Yong Zhang
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121301 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Low-noise amplification of dissipative Kerr soliton microcomb lines via optical injection locking lasers
Qiang Zhang, Boyuan Liu, Qin Wen, Jinhui Qin, Yong Geng, Qiang Zhou, Guangwei Deng, Kun Qiu, and Heng Zhou
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121401 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Q-switched mode-locked multimode fiber laser based on a graphene-deposited multimode microfiber
Jia-Wen Wu, Yu-Xin Gao, Xu-Bin Lin, Jin-Gan Long, Hu Cui, Zhi-Chao Luo, Wen-Cheng Xu, and Ai-Ping Luo
We report Q-switched mode-locked (QML) pulses generation in an Yb-doped multimode fiber (MMF) laser by using a graphene-deposited multimode microfiber (GMM) for the first time, to the best of our knowledge. The single-wavelength QML operation with the central wavelength tunable from 1028.81 nm to 1039.20 nm and the dual-wavelength QML operation with the wavelength spacing tunable from 0.93 nm to 5.79 nm are achieved due to the multimode interference filtering effect induced by the few-mode fiber and MMF structure and the GMM in the cavity. Particularly, in the single-wavelength QML operation, the fifth harmonic is also realized owing to the high nonlinear effect of the GMM. The obtained results indicate that the QML pulses can be generated in the MMF laser, and such a flexible tunable laser has promising applications in optical sensing, measuring, and laser processing.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121402 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Non-mechanical beam scanner based on VCSEL integrated amplifier with resonant wavelength detuning design
Shanting Hu, Xiaodong Gu, Masanori Nakahama, and Fumio Koyama
We demonstrate the non-mechanical beam steering and amplifier operation of a vertical cavity surface emitting laser (VCSEL) integrated Bragg reflector waveguide amplifier with a cut-off wavelength detuning design, which enables unidirectional lateral coupling, continuous electrical beam steering, and diffraction-limited divergence angle. We present the modeling of the proposed structure for unidirectional coupling between a seed single-mode VCSEL and slow-light amplifier. We also present the detailed operating characteristics including the near-field and far-field patterns, light/current characteristics, and lasing spectrum. The experimental measurements exhibit a single-mode output of over 8 mW under CW operation, a continuous beam steering range of 16°, and beam divergence below 0.1° as an optical beam scanner. The integrated amplifier length is as small as 0.9 mm, and thus we could expect much higher powers and higher resolution points by increasing the amplifier lengths.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121403 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Long-term frequency-stabilized optical frequency comb based on a turnkey Ti:sapphire mode-locked laser
Guang Yang, Haosen Shi, Yuan Yao, Hongfu Yu, Yanyi Jiang, Albrecht Bartels, and Longsheng Ma
We report a long-term frequency-stabilized optical frequency comb at 530–1100 nm based on a turnkey Ti:sapphire mode-locked laser. With the help of a digital controller, turnkey operation is realized for the Ti:sapphire mode-locked laser. Under optimized design of the laser cavity, the laser can be mode-locked over a month, limited by the observation time. The combination of a fast piezo and a slow one inside the Ti:sapphire mode-locked laser allows us to adjust the cavity length with moderate bandwidth and tuning range, enabling robust locking of the repetition rate (fr) to a hydrogen maser. By combining a fast analog feedback to pump current and a slow digital feedback to an intracavity wedge and the pump power of the Ti:sapphire mode-locked laser, the carrier envelope offset frequency (fceo) of the comb is stabilized. We extend the continuous frequency-stabilized time of the Ti:sapphire optical frequency comb to five days. The residual jitters of fr and fceo are 0.08 mHz and 2.5 mHz at 1 s averaging time, respectively, satisfying many applications demanding accuracy and short operation time for optical frequency combs.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121405 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Influence of annealing temperature on the performance of TiO2/SiO2 nanolaminated films
Yun Cui, Yuanan Zhao, Ge Zhang, Meiping Zhu, Chen Song, Chunxian Tao, Tan Shu, and Jianda Shao
Different laminated structures of TiO2/SiO2 composite film were prepared via atomic layer deposition (ALD) on alumina substrates. The effect of the annealing temperature in the air on the surface morphologies, crystal structures, binding energies, and ingredient content of these films was investigated using X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. Results showed that the binding energy of Ti and Si increased with decrease of the Ti content, and the TiO2/SiO2 nanolaminated films exhibited a complex bonding structure. As the annealing temperature increased, the thickness of the nanolaminated films decreased, and the density and surface roughness increased. An increase in the crystallization temperature was proportional to the SiO2 content in TiO2/SiO2 composite film. The annealing temperature and thin thickness strongly affected the phase structure of the ALD TiO2 thin film. To be specific, the TiO2 thin film transformed into an anatase phase from an amorphous phase after an increase in the annealing temperature from 400°C to 550°C, and the TiO2 film exhibited an anatase phase until the annealing temperature reached 850°C, owing to its extremely small thickness. The annealing process caused the Al ions in the substrate to diffuse into the films and bond with O.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121406 (2021)
Light-Matter Interaction
High period frequency LIPSS emerging on 304 stainless steel under the irradiation of femtosecond laser double-pulse trains
Yifei Li, Jie Hu, Wei Liu, Jiangang Yin, and Jiangang Lu
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123801 (2021)
Nanophotonics, Metamaterials, and Plasmonics
Multifrequency superscattering pattern shaping
Yao Qin, Jinying Xu, Yineng Liu, and Huanyang Chen
Multifrequency superscattering is a phenomenon in which the scattering cross section from a subwavelength object simultaneously exceeds the single-channel limit at multiple frequency regimes. Here, we achieve simultaneously, within a graphene-coated subwavelength structure, multifrequency superscattering and superscattering shaping with different engineered scattering patterns. It is shown that multimode degenerate resonances at multiple frequency regimes appearing in a graphene composite structure due to the peculiar dispersion can be employed to resonantly overlap electric and magnetic multipoles of various orders, and, as a result, effective multifrequency superscattering with different engineered angular patterns can be obtained. Moreover, the phenomena of multifrequency superscattering have a high tolerance to material losses and some structural variations. Our work should anticipate extensive applications ranging from emission enhancing, energy harvesting, and antenna design with improved sensitivity and accuracy due to multifrequency operation.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123601 (2021)
Nanophotonics, Metamaterials, and Plasmonics
Strong coupling with absorption and emission features of Ag@Au hollow nanoshells interacting with J-aggregated dye molecules
Tianchen Zhao, Qiang Ma, Yajie Bian, Yuyi Zhang, Yiting Liu, Xiaolei Zhang, Botao Wu, E Wu, Shitao Lou, and Qingyuan Jin
We investigate the strong coupling from 5,5’,6,6’-tetrachloro-1,1’-diethyl-3,3’-di(4-sulfobutyl)-benzimidazolocarbocyanine (TDBC) molecules near pure nano-triangular Ag prisms or Ag@Au hollow nanoshells. When TDBC molecules are deposited on pure Ag nanoprisms or Ag@Au hollow nanoshells with the plasmonic resonance peak, matching very closely with the absorption band of TDBC J-aggregates, obvious Rabi splitting can be observed due to the strong coupling regime. Meanwhile, the photoluminescence intensity decreased with the increasing of the temperature, verifying the decreasing plasmon–exciton coupling interaction in the higher temperature. Our experimental results are coincident with the simulation results calculated by finite-difference time-domain method.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123602 (2021)
Optical Materials
Ultra-fast and low-cost fabrication of transparent paper
Lulin Wei, Jie Li, Haohao Wang, Shuhong Nie, Wenming Su, Dafang Huang, and Mingwei Zhu
Transparent paper is a kind of promising and environmentally friendly material. In this study, we show that transparent paper can be fabricated in an ultra-fast and low-cost way. This low-cost top-down method only takes three steps of cell separation, lignin removal, and cold pressing to obtain a high-quality transparent paper. The fabrication time is further reduced, and the resulted transparent paper shows high transparency up to 90.3%. The application as a substrate material for transparent and flexible electronic devices is demonstrated by emulating the printed circuit on the prepared transparent paper. This top-down method will greatly promote the market-oriented applications of transparent paper as an environment friendly material.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 121601 (2021)
Quantum Optics and Quantum Information
Population dynamics of ultra-cold atoms interacting with radiation fields in the presence of inter-atomic collisions
E. Ghasemian, and M. K. Tavassoly
We investigate the dynamics of a system that consists of ultra-cold three-level atoms interacting with radiation fields. We derive the analytical expressions for the population dynamics of the system, particularly, in the presence and absence of nonlinear collisions by considering the rotating wave approximation (RWA). We also reanalyze the dynamics of the system beyond RWA and obtain the state vector of the system to study and compare the time behavior of population inversion. Our results show that the system undergoes two pure quantum phenomena, i.e., the collapse–revival and macroscopic quantum self-trapping due to nonlinear collisional interactions. The occurrence of such phenomena strongly depends on the number of atoms in the system and also the ratio of interaction strengths in the considered system. Finally, we show that the result of the perturbed time evolution operator up to the second-order is in agreement with the numerical solution of the Schrödinger equation. The results presented in the paper may be useful for the design of devices that produce a coherent beam of bosonic atoms known as an atom laser.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 122701 (2021)
Spectroscopy
Influence of a dielectric decoupling layer on the local electric field and molecular spectroscopy in plasmonic nanocavities: a numerical study
Gong Chen, Jiazhe Zhu, and Xiaoguang Li
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123001 (2021)
Ultrafast Optics and Attosecond/High-Field Physics
Time-energy analysis of the photoionization process in a double-XUV pulse combined with a few-cycle IR field
Yi Jia, Li Guo, Shilin Hu, Xinyan Jia, Daihe Fan, Ronghua Lu, Shensheng Han, and Jing Chen
We calculate the time-energy distribution (TED) and ionization time distribution (ITD) of photoelectrons emitted by a double-extreme-ultraviolet (XUV) pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation. For a double-XUV pulse, besides two identical broad distributions generated by two XUV pulses, many interference fringes resulting from the interference between electrons generated, respectively, by two pulses appear in the TED. After adding an IR field, the TED intuitively exhibits the effect of the IR field on the electron dynamics. The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields, the origin of which is attributed to the change of the electric field induced by the IR field. Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.
Chinese Optics Letters
  • Publication Date: Dec. 10, 2021
  • Vol.19 Issue, 12 123201 (2021)
Research ArticlesVol.19, Iss.11-Nov..1,2021
Biophotonics
Review of photoacoustic imaging for microrobots tracking in vivo [Invited]
Dengfeng Li, Yachao Zhang, Chao Liu, Jiangbo Chen, Dong Sun, and Lidai Wang
Microrobots-assisted drug delivery and surgery have been always in the spotlight and are highly anticipated to solve the challenges of cancer in situ treatment. These versatile small biomedical robots are expected to realize direct access to the tumor or disease site for precise treatment, which requires real-time and high-resolution in vivo tracking as feedback for the microrobots’ actuation and control. Among current biomedical imaging methods, photoacoustic imaging (PAI) is presenting its outstanding performances in the tracking of microrobots in the human body derived from its great advantages of excellent imaging resolution and contrast in deep tissue. In this review, we summarize the PAI techniques, imaging systems, and their biomedical applications in microrobots tracking in vitro and in vivo. From a robotic tracking perspective, we also provide some insight into the future of PAI technology in clinical applications.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111701 (2021)
Fiber Optics and Optical Communications
Compensation of turbulence-induced wavefront aberration with convolutional neural networks for FSO systems
Min’an Chen, Xianqing Jin, Shangbin Li, and Zhengyuan Xu
To reduce the atmospheric turbulence-induced power loss, an AlexNet-based convolutional neural network (CNN) for wavefront aberration compensation is experimentally investigated for free-space optical (FSO) communication systems with standard single mode fiber-pigtailed photodiodes. The wavefront aberration is statistically constructed to mimic the received light beams with the Zernike mode-based theory for the Kolmogorov turbulence. By analyzing impacts of CNN structures, quantization resolution/noise, and mode count on the power penalty, the AlexNet-based CNN with 8 bit resolution is identified for experimental study. Experimental results indicate that the average power penalty decreases to 1.8 dB from 12.4 dB in the strong turbulence.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 110601 (2021)
Fiber Optics and Optical Communications
Signal transmission of 4 GHz beyond the system bandwidth in UV-C LED communication based on temporal ghost imaging
Mengyin Jin, Zeyuan Qian, Xinwei Chen, Xugao Cui, Ke Jiang, Xiaojuan Sun, Dabing Li, and Pengfei Tian
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 110602 (2021)
Fiber Optics and Optical Communications
Gain and laser performance of heavily Er-doped silica fiber fabricated by MCVD combined with the sol-gel method
Qiubai Yang, Yan Jiao, Chunlei Yu, Chongyun Shao, Fengguang Lou, Shikai Wang, Lei Zhang, Qiuhong Yang, and Lili Hu
In this work, a heavily Er-doped fiber with an 8 µm core diameter and a numerical aperture of 0.13 was prepared by the modified chemical vapor deposition (MCVD) technique combined with the sol-gel method. The background loss and absorption coefficient at 1530 nm were measured to be 20 dB/km and 128 dB/m, respectively. Thanks to the sol-gel method, the fiber showed a good doping homogeneity, which was confirmed through unsaturable absorption measurement. The net gains of three 25, 45, and 75-cm-long fibers were measured in the range of 1520 to 1600 nm, and the highest gain reached above 23 dB at both 1530 and 1560 nm in 25 and 75-cm-long fibers, respectively. The short-cavity laser performance was measured using centimeter-scale fibers. The maximum output power of 12 mW was demonstrated in a 6.5-cm-long active fiber with a slope efficiency of 20.4%. Overall, the prepared heavily Er-doped silica fiber is a promising item to be applied in a high-repetition-rate or single-frequency fiber laser.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 110603 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Frequency-modulated continuous-wave dual-frequency LIDAR based on a monolithic integrated two-section DFB laser
Changsheng Wang, Yunshan Zhang, Jilin Zheng, Jin Li, Zhenxing Sun, Jianqin Shi, Lianyan Li, Rulei Xiao, Tao Fang, and Xiangfei Chen
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111402 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Adjustable-free and movable Nd:YVO4 thin disk laser based on the telecentric cat’s eye cavity
Wei Wang, Yongxi Gao, Di Sun, Xiao Du, Jie Guo, and Xiaoyan Liang
In this paper, we propose and demonstrate an adjustable-free and movable Nd:YVO4 thin disk laser based on the telecentric cat’s eye cavity. We design a V-shaped laser cavity containing two reflectors with Nd:YVO4 thin disks as the gain medium. The experimental results from the traditional plane-plane cavity, plane-telecentric cat’s eye cavity, and double telecentric cat’s eye cavity are compared. They show that plane-telecentric cat’s eye cavity laser can keep operating at the adjustable-free range of -6° to +6°, which is up to 60 times better than that of traditional plane-plane cavity. In the double telecentric cat’s eye case, the adjustable-free range is improved to -13° to +13°. Additionally, in the case of the double telecentric cat’s eye cavity, the output telecentric cat’s eye can achieve free movement within the horizontal range of ±20 mm.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111403 (2021)
Lasers, Optical Amplifiers, and Laser Optics
Simultaneous tailoring of longitudinal and transverse mode inside an Er:YAG laser
Rui Song, Xueting Liu, Shiyao Fu, and Chunqing Gao
In this paper, we demonstrate a scheme to tailor both longitudinal and transverse modes inside a laser cavity and constitute an eye-safe single longitudinal mode Er:Y3Al5O12 (Er:YAG) vector laser. A q-plate is employed as a spin-orbital conversion element to modulate the transverse mode and obtain cylindrical vector beams. An optical isolator is employed as a non-reciprocal element for the ring cavity to enforce unidirectional operation and achieve single longitudinal oscillation. The characteristics of power, transverse intensity, and polarization spectrum of the output beams are observed. The observed typical single longitudinal mode and highly matched special polarizations prove the successful tailoring of both longitudinal and transverse modes.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111404 (2021)
Microwave Photonics
Linearized wideband and multi-carrier link based on TL-ANN
Enji Liu, Zhenming Yu, Zhiquan Wan, Liang Shu, Kaixuan Sun, Lili Gui, and Kun Xu
The analog photonics link (APL) is widely used in microwave photonics. However, in wideband and multi-carrier systems, the third inter-modulation distortion (IMD3) and cross-modulation distortion (XMD) will jointly limit the spurious-free dynamic range (SFDR) of links. In this paper, we experimentally present a linearized wideband and multi-carrier APL, in which the IMD3 and XMD are mitigated simultaneously by using artificial neural networks with transfer learning (TL-ANN). In this experiment, with different artificial neural networks, which are trained with the knowledge obtained from the two- or three-sub-carrier system, the IMD3 and XMD are suppressed by 21.71 dB and 11.11 dB or 22.38 dB and 16.73 dB, and the SFDR is improved by 13.4 dB or 14.3 dB, respectively. Meanwhile, compared with previous studies, this method could reduce the training time and training epochs to 16% and 25%.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 113901 (2021)
Nonlinear Optics
All-optical carrier recovery for self-homodyne detection via injection locked Brillouin laser in whispering-gallery-mode microcavity
Boyuan Liu, Yong Geng, Qiang Zhang, Xinjie Han, Jing Xu, Heng Zhou, and Kun Qiu
We demonstrate comprehensive investigation of the injection locking dynamics of a backscattered Brillouin laser in silica whispering-gallery-mode microcavity. Via injection locking, the Brillouin laser acquires highly correlated phase with the seed laser, enabling ultra-narrow bandwidth, high gain, and coherent optical amplification. Also, for the first time, to the best of our knowledge, the injection locked Brillouin laser is utilized to implement all-optical carrier recovery from coherent optical data signals. We show that by using the injection locked Brillouin laser as a local oscillator for self-homodyne detection, high-quality data receiving can be realized, even without traditional electrical compensations for carrier frequency and phase drifts.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111901 (2021)
Nonlinear Optics
Performance comparison of lithium-niobate-based extremely high-field single-cycle terahertz sources [Invited]
György Tóth, László Pálfalvi, Szabolcs Turnár, Zoltán Tibai, Gábor Almási, and János Hebling
Tilted-pulse-front-pumping (TPFP) lithium-niobate terahertz (THz) pulse sources are widely used in pump-probe and control experiments since they can generate broadband THz pulses with tens of microjoules of energy. However, the conventional TPFP setup suffers from limitations, hindering the generation of THz pulses with peak electric field strength over 1 MV/cm. Recently, a few setups were suggested to mitigate or even eliminate these limitations. In this paper, we shortly review the setups that are suitable for the generation of single-cycle THz pulses with up to a few tens of megavolts/centimeter focused electric field strength. The THz pulses available with the new layouts pave the way for previously unattainable applications that require extremely high electric field strength and pulse energy in the multi-millijoule range.
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111902 (2021)
Optical Design and Fabrication
Design of multi-passband polymer multilayer film and its application in photovoltaic agriculture
Ming Li, Yang Liu, Fangxin Zhang, Xinyu Zhang, Zhisen Zhang, Altyeb Ali Abaker Omer, Shutao Zhao, and Wen Liu
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 112201 (2021)
Optical Design and Fabrication
Optical design of a compact and high-transmittance compressive sensing imaging system enabled by freeform optics
Dewen Cheng, Hailong Chen, Tong Yang, Jun Ke, Yang Li, and Yongtian Wang
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 112202 (2021)
Optical Materials
Mid-infrared flat-topped broadband chiral helix metamaterials based on indium tin oxide and their chiral properties
Wentao Zhang, Weijie Shi, Hui Guo, and Changchun Yan
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 111601 (2021)
Quantum Optics and Quantum Information
Sequential 3 → 1 quantum random access code utilizing unsharp measurements
Zhiguang Pang, Jiang Gao, Tianlei Hou, Min Wei, Jian Li, and Qin Wang
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 112701 (2021)
Solar Energy and Photovoltaics
Incorporation of Ag into Cu(In,Ga)Se2 films in low-temperature process
Zhaojing Hu, Yunxiang Zhang, Shuping Lin, Shiqing Cheng, Zhichao He, Chaojie Wang, Zhiqiang Zhou, Fangfang Liu, Yun Sun, and Wei Liu
Chinese Optics Letters
  • Publication Date: Nov. 10, 2021
  • Vol.19 Issue, 11 114001 (2021)
ReviewsVol.19, Iss.10-Oct..1,2021
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: Oct. 10, 2021
  • Vol.19 Issue, 10 102202 (2021)
Research ArticlesVol.19, Iss.10-Oct..1,2021
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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 2021
  • Vol.19 Issue, 10 101201 (2021)
Instrumentation, Measurement, and Optical Sensing
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: Oct. 10, 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: Oct. 10, 2021
  • Vol.19 Issue, 10 101301 (2021)
Integrated Optics
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: Oct. 10, 2021
  • Vol.19 Issue, 10 101302 (2021)
Lasers, Optical Amplifiers, and Laser Optics
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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 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: Oct. 10, 2021
  • Vol.19 Issue, 10 103201 (2021)