Liu Kexuan   He Zehao   Cao Liangcai  

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The bidirectional error diffusion (BERD) algorithm is free from random phase modulation that introduces speckle noise on the reconstructed images, compared with other computer-generated phase-only hologram (POH) approaches. During the POH generation process, the amplitudes of all pixels are traditionally set to one for diffusing the errors to their neighborhood unprocessed pixels. In this paper, we reveal that the reconstruction quality depends on the uniform amplitude value for different object pattern. The pattern-adaptive bidirectional error diffusion (PA-BERD) algorithm is proposed for high-quality holographic reconstruction. The optimized amplitude value can be acquired for each object pattern and each propagation distance. The PA-BERD based POHs have shown higher reconstruction quality than traditional BERD based POHs in simulations as well as optical experiments.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第5期 pp.05      

jiang zengshun   An Xingqi   Zhang Yuqin   Liu Xuan   Qin Xifeng   Zhao Yanjie   Wang Huilin   Liu Guiyuan   song hongsheng  

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After the 3D self-affine fractal random surface simulated, we use the optical scattering theory to calculate the deep Fresnel region speckle (DFRS) under considering the more strict shadowing effect. The evolution of DFRS with the scattering distance and the intensity probability distribution were studied. It is found that the morphology of the scatterer has an antisymmetric relationship with the intensity distribution of DFRS, and the effect of micro-lenses on the scattering surface causes the intensity probability distribution of DFRS to deviate from the Gaussian speckle in the high light intensity area.

       PDF全文 (下载：5)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Zhao Yuqing   Wang Qiangguo   Meng Lihua   Yao Yongping   Liu Shande   Cui Na   su liangbi   Zheng Lihe   Zhang Huiyun   Zhang Yuping  

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The anisotropy of thermal property in Yb,Nd:Sc₂SiO₅ crystal are investigated from the temperature of 293 to 573 K. Based on the systematical study of thermal expansion, thermal diffusivity and specific heat, the thermal conductivity in Yb,Nd:Sc₂SiO₅ crystal orientated at (100), (010), (001) and (406) is calculated to be 3.46, 2.60, 3.35 and 3.68 W/(m·K), respectively. The laser output anisotropy of continuous-wave (CW) and tunable laser are characterized, accordingly. A maximum output power of 6.09 W is achieved in Yb,Nd:Sc₂SiO₅ crystal with (010) direction, corresponding to a slope efficiency of 48.56 %. The tuning wavelength ranges in Yb,Nd:Sc₂SiO₅ crystal orientated at (100), (010) and (001) is 68, 67 and 65 nm, separately. The effects of thermal properties on CW laser performance are discussed.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Qiu Feng   Han Yu  

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Electro-optic (EO) ring resonator modulators have a number of telecommunications and scientific applications, including analog optical links, optical signal processing, and frequency comb generation. Among the EO materials used to fabricate ring modulators, EO polymer has many promising characteristics, including a high EO coefficient of 100-200 pm/V (3-7 times larger than that of LiNbO3), an ultrafast EO response time (<10 fs), a low dielectric constant (3 to 4) with very little dispersion up to at least 250 GHz and a straightforward spin-coating fabrication process. These inherent characteristics will be able to combine excellent EO properties with simple processing to achieve exceptional performance in a variety of high-speed optical modulation and sensing devices. This review focuses on the research and recent development of the ring resonator modulators based on EO polymer. The first part describes the operation principle of EO ring resonator modulators, such as modulation mechanism, EO tunability and 3-dB bandwidth. Subsequently, the emphasis is placed on the discussion of the ring modulators with EO polymer as the waveguide core and the improvement of EO modulation by using EO polymer / titanium dioxide hybrid core. At the end, a series of EO polymer on silicon platforms including slot modulators, etching-free modulators and athermal modulators are reviewed.

       PDF全文 (下载：0)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Shi Qiangshi   Shi Qiangshi   Jin Xia   Wu Qiannan   Huang Cheng   Sun Baoyin   Gao Lei   Xu Yadong   Fu Yangyang  

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In this work, inspired by advances in twisted two dimensional materials, we design and study a new type of optical bi-layer metasurface system, each based on subwavelength metal slit arrays with phase gradient modulation, referred as metagratings (MG). It is shown that due to the found reversed diffraction law, the interlayer interaction that can be simply adjusted by the gap size, can produce a transition from optical beam splitting to high-efficiency asymmetric transmission of incident light from two opposite directions. Our results provide new physics and some advantages for designing subwavelength optical devices to realize efficient wavefront manipulation and one-way propagation.

       PDF全文 (下载：2)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Cao Jiayuan   Li Na   Bai Ya   Liu Peng   Li Ruxin  

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We present a velocity-gauge model for the generation of even-order high harmonics, and reveal that the even-order harmonics originate from the multiple-step transitions among the energy bands in momentum space, while the odd-order harmonics mainly from the direct transitions. The lower valence band is found vital for the generation of even harmonics. Relative intensity of even-order harmonics versus the odd orders is calculated and shows a growing trend as the laser field amplitude increases.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Li Siqiao   Zhang Tiantian   Qiao Yaojun   Zhou Ji  

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This paper proposed a hybrid layered asymmetrically clipped optical single-carrier frequency-division multiplexing (HLACO-SCFDM) scheme for dimmable visible light communication. It designs a signal structure that combines LACO-SCFDM and negative LACO-SCFDM in proportion for improving the inherent weaknesses of orthogonal frequency division multiplexing (OFDM)-based dimmable schemes and further enhancing the system performance. Compared to HLACO-OFDM-based dimming scheme, it obtains lower bit error ratio and enables efficient communication over broader dimming range. Its spectral efficiency realizes 2.875 bit/s/Hz within the dimming range of 30%-70%, and the attainable average spectral efficiency gains exceed at least 19.21% compared to other traditional dimmable schemes.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Meng Fangyuan   Yu Hongyan   Zhou Xuliang   Li Yajie   Wang Mengqi   Yang Wenyu   Chen Weixi   Zhang Yejin   Pan Jiaoqing  

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Gas sensing for measurement of gas component, concentrations and other parameters plays an important role in many fields. In this letter, a micro-ring resonator laser used for gas sensing is experimentally demonstrated. The multi-quantum-wells micro-ring laser based on whispering-gallery modes (WGMs) with an annular resonator and an output waveguide was fabricated. A single-mode laser with a wavelength of 1746.4 nm was fabricated for the first time experimentally. The output power of 1.65 mW under 40 mA injection current was obtained with a side-mode suppression ratio (SMSR) over 33 dB.

       PDF全文 (下载：0)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Zhu Yihuai   Zheng Zhijian   Ge Xiaogang   Du Geguo   Ruan Shuangchen   Guo Chunyu   Yan Peiguang   Hua Ping   Xia Linzhong   Lue Qitao  

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We experimentally demonstrate an all-fiber supercontinuum source that covers the spectral region ranging from visible to mid-infrared. The ultra-broadband supercontinuum is realized by pumping cascaded photonic crystal fiber and highly-nonlinear fiber with a 1/1.5 μm dual-band pump source. A maximum output power of 9.01 W is achieved using the system, which is the highest power ever achieved from a supercontinuum source spanning from visible to mid-infrared.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Pan Long   Deng Chenjin   yu cuiping   yue shuai   Gong Wenlin   Han Shensheng  

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The influence of the sparsity of random speckle illumination on traditional ghost imaging (GI) and ghost imaging via sparse constrains (GISC) in noise environment is investigated. The experiments demonstrate that both GI and GISC obtain their best imaging quality when the sparsity of random speckle illumination is 0.5, which is also explained by some parameters such as detection signal to noise ratio and mutual coherence of measurement matrix.

       PDF全文 (下载：0)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Wang Senyu   Ma Yiwei   Xiaoyang Li   Yi Yang   Sun Cuiting   Lin Jingyu   Chengguo Tong   Li Yuxiang   Geng Tao   Sun weimin   Yuan Libo  

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In this Letter, we propose and investigate a compact optical fiber sensor which aims to measure the torsion in both amount and direction with high sensitivity. This sensor is configured by a triangular-prism-shaped long-period fiber grating which is fabricated by the high frequency CO2 laser polished method. The unique design of the triangular shaped structure breaks the rotational symmetry of the optical fiber and provides the high sensitivity for torsion measurement. In preliminary experiments, the torsion response of the sensor achieves a good stability and linearity. The torsion sensitivity is 0.54 nm/(rad/m), which renders the proposed structure a high sensitive torsion sensor.

       PDF全文 (下载：0)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

He Chong   Zhou Cheng   Zhou Qian   Xie Shiyi   Tian Jiajun   Yao Yong  

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A fiber optic sensor for the simultaneous measurement of strain and temperature is proposed and experimentally demonstrated based on Fabry–Pérot (FP) interference and the antiresonant (AR) mechanism. The sensor was implemented using a single-mode fiber (SMF)–hollow-core fiber (HCF)–SMF structure. A temperature sensitivity of 21.11 pm/°C was achieved by tracing the troughs of the envelope caused by the AR mechanism and a strain sensitivity of 2 pm/με was achieved by detecting the fine fringes caused by the FP cavity. The results indicate that the sensor is stable and reliable.

       PDF全文 (下载：10)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Tan Chao   Zhao Linjie   Chen Mingjun   Cheng Jian   Yin Zhaoyang   Liu Qi   Yang Hao   Liao Wei  

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In order to reveal the evolution mechanism of repaired morphology and the material’s migration mechanism on the crack surface in the process of CO2 laser repairing surface damage of fused silica optics, two multi-physics coupling mathematical models with different scales are developed respectively. The physical problems, such as heat and mass transfer, material phase transition, melt flow, evaporation removal and crack healing, are analyzed. Studies show that material ablation and the gasification recoil pressure accompanying the material splash are the leading factors in forming the Gaussian crater with raised rim feature. The use of low-power laser for a long time can fully melt the material around the crack before healing, which can greatly reduce the size of the residual air layer. Combined with the experimental research, the methods to suppress the negative factors (e.g., raised rim, deposited debris, air bubbles) in CO2 laser repairing process are proposed.

       PDF全文 (下载：4)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Wang Kaile   Wen Zengrun   Chen Haowei   lu baole   Bai Jintao  

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We reported a wavelength-flexible all-polarization-maintaining self-sweeping fiber laser based on the intracavity loss tuning brought by the bent optical fiber. The bidirectional cavity structure achieved the self-sweeping effect due to the appearance of the dynamic grating in the active fiber with spatial hole burning effect. Under this, a section of fiber was bent into a circle for adjusting the loss of the cavity. With a descending diameter of bent fiber circle, the sweeping range moves to the shorter wavelength and covers a wide range from 1055.6 to 1034.6 nm eventually. Both the initial wavelength of self-sweeping regime and the threshold of fiber laser show exponential correlation with the diameter of the circular fiber. Our work provides a compact and low-cost way to achieve the broad wavelength-flexible self-sweeping operation.

       PDF全文 (下载：11)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Yu Ye   Song Yiwen   Chen Tao   Wang Huaiqiang   Zhuang Songlin   Cheng Qingqing  

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The Floquet topological insulators (FTI) have been used to study the dynamic quantum system’s topological features within the band structure. However, it is difficult to directly observe the dynamic modulation of the band structure in FTI. Here, we implemented the dynamic Su-Schrieffer-Heeger (SSH) model in periodically curved waveguides to explore new behaviors in FTI using light field evolutions. By changing the driven frequency, near-field evolutions of light in the high-frequency (HF) curved waveguide array exhibit equivalence with the behaviors in the straight array. Furthermore, at the modest driven frequency, the field evolutions in the system show the boundary propagation, which is related to the topological edge modes. Finally, we hope the curved waveguides may open up profound and applicable possibilities for the further development of Floquet engineering in periodically-driven systems, ranging from condensed matter physics to photonics.

       PDF全文 (下载：2)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Gu Jun-Hao   Sun Shuai   Xu Yao-Kun   Lin Huizu   Liu Weitao  

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Applications of ghost imaging is limited by the requirement on large number of samplings. Based on the observation that the edge area contains more information thus requires larger number of samplings, we propose a feedback ghost imaging strategy, to reduce the number of required samplings. The field of view is gradually concentrated onto the edge area, with the size of illumination speckles getting smaller. Experimentally, images of high quality and resolution are successfully reconstructed with much fewer samplings and linear algorithm.

       PDF全文 (下载：4)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Feng Ting   Zhu Yunhao   Xie Yejing   Ta Dean   Yuan Jie   Cheng Qian  

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This study investigated the feasibility of photoacoustic (PA) imaging of bone and characterization of bone features. By conducting the experiments on the bovine femoral heads ex vivo, the light and ultrasonic penetration in bones was studied, together with the depth of PA imaging and measurement in bones. Then, the possibility of PA imaging of bones by raster scanning of the focusing transducer was studied. The micro-CT images of the bovine ribs with and without ethylenediaminetetraacetic acid (EDTA) treatment indicated that the PA images could present the changes of bone microstructure result from the EDTA treatment. By using PA spectral analysis (PASA), the bone samples with and without the treatment of EDTA solution can be distinguished, and the microstructures can be characterized. This study was based on the bovine bone whose size comparable to human bones, suggesting that PA technology can be used as a novel bone diagnostic technique.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第12期 pp.12      

Zhong Xin   Wang Xinwei   Sun Liang   Zhou Yan  

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An enhancement method of rapid lifetime determination is proposed for time-resolved fluorescence imaging to discriminate substances with approximate fluorescence lifetime in forensic examination. In the method, an image-Exclusive-OR treatment with filter threshold adaptively chosen is presented to extract region of interest from dual-gated fluorescence intensity images, and then the fluorescence lifetime image is reconstructed based on rapid lifetime determination algorithm. Furthermore, a max-min threshold filtering is developed to automatically realize visualization enhancement of the lifetime image. In proof experiments, compared with traditional fluorescence intensity imaging and rapid lifetime determination method, the proposed method automatically distinguishes altered and obliterated document written by two brands of highlighters with the same color and close fluorescence lifetime.

       PDF全文 (下载：0)        Chinese Optics Letters ，2021年第19卷第4期 pp.04      

Chen Li   Kumar Singh Rakesh   Dogariu Aristide   Chen Ziyang   Pu Jixiong  

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Encoding information using the topological charge of vortex beams has been proposed for optical communications. The conservation of the topological charge on propagation and the detection of the topological charge by a receiver are significant in these applications and have been well established in free-space. However, when vortex beams enter a diffuser, the wavefront is distorted, leading to a challenge in the conservation and detection of the topological charge. Here, we present a technique to measure the topological charge of a vortex beam obscured in the randomly scattered light. The results of the numerical simulations and experiments are presented and are in good agreement. In particular, only a single-shot measurement is required to detect the topological charge of vortex beams, indicating that the method is applicable to a dynamic diffuser.

       PDF全文 (下载：5)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Wang Pengwei   Wang Chenglong   yu cuiping   yue shuai   Gong Wenlin   Han Shensheng  

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We propose a color ghost imaging approach where the object is illuminated by three-color non-orthogonal random patterns and the object's reflection/transmission information is received by only one single-pixel detector, and both the sparsity constraint and non-local self-similarity of the object are utilized in the image reconstruction process. Numerical simulated results demonstrate that the imaging quality can be obviously enhanced by ghost imaging via sparsity constraint and non-local self-similarity (GISCNL), compared with the reconstruction methods where only the object’s sparsity is used. Factors affecting the quality of GISCNL, such as the measurement number and the detection SNR, are also studied.

       PDF全文 (下载：1)        Chinese Optics Letters ，年第卷第期 pp.      

Pang Chi   Li Rang   Li Ziqi   Dong Ningning   Wang Jun   Ren Feng   Chen Feng  

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Copper nanoparticles (Cu NPs) are synthesized under the near-surface region of the Nd:YAG crystal by direct Cu+ ions implantation. Subsequently, monolithic ridge waveguide with embedded Cu NPs is fabricated by C4+ ions implantation and diamond saw dicing. Nonlinear optical response of the sample is investigated by Z-scan technique and pronounced saturable absorption is observed at 1030 nm femtosecond laser. Based on the obvious saturable absorption of Cu NPs embedded Nd:YAG crystal, 1 μm monolithic mode-locked pulsed waveguide laser is implemented by evanescent field interaction between NPs and waveguide modes, reaching the pulse duration of 24.8 ps and repetition rate of 7.8 GHz. The work combines waveguides with NPs, achieving pulsed laser devices based on monolithic waveguide chip.

       PDF全文 (下载：4)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Zhukova Lia   Salimgareev Dmitrii   Lvov Alexandr   Lashova Anastasiya   Korsakov Alexandr   Belousov Dmitrii  

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The article is devoted to the technology for obtaining optical ceramics of AgBr – TlI and AgBr-TlBr0.46I0.54 systems and manufacture samples with different compositions. The new heterophase crystal ceramics is transparent without absorption windows in the spectral range from 1.0 to 60.0 microns. In the ceramics' transparency spectra based on the AgBr – TlI and AgBr – TlBr0.46I0.54 systems fusibility diagrams, with an increase in the thallium halides mass fraction, as well as the replacement of bromine ion with iodine, the maximum transparency shifts to a long infrared region.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Zhu Jing   Xu Shiqing   Lei Lei   Huang feifei   Xiao Zhen  

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Up-converting(UC) perovskite Er3+-doped PbTiO3 (Er-PTO) nanoparticles with green and red emissions were synthesized via hydrothermal method. The UC properties were manipulated by adjusting the concentration of Er3+ ions dopant. The green emission intensity was decreased as the doping concentration increased from 1 mol% to 4 mol%, whereas the red emission intensity was increased. The influences of Er3+ ions on the temperature-sensing performance were further investigated. The results demonstrated that Er-PTO nanoparticles with doping 1 mol% concentration of Er3+ ions possessed a sensitivity of 3.1×10-3 K-1 at 475 K, presenting a high potential in optical heating devices.

       PDF全文 (下载：3)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Wang Guanxue   Miao Yu   Li Yang   Shan Xinzhi   Gao Xiumin  

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The unevenly distributed Lorentz-Gaussian beams are difficult to reproduce in practice, (R2-Q1) because it requires modulation in both amplitude and phase terms. Here a new linearly polarized Lorentz-Gauss beam modulated by a helical axicon (LGB-HA) is calculated and the two various experimental generation methods of this beam, (R2-2-Q1) Fourier Transform Method (FTM) and Complex-Amplitude Modulation (CAM) method are depicted. Compared with Fourier Transform Method, Complex-Amplitude Modulation method can modulate the phase and amplitude simultaneously by only one reflection-type phase-only liquid crystal spatial light modulator. Both the two methods are coincident with the numerical results. (R1-Q6) (R2-Q2) Yet the Complex-Amplitude Modulation is more simple, efficient and has a higher degree of conformance through data comparison. (R1-Q6) (R2-Q2) In addition, considering some barriers existed in shaping and reappearing the complicated Lorentz-Gauss beam with heterogeneous distribution, the evolution regularities of the beams with different parameters (B, n, m) were also implemented.

       PDF全文 (下载：5)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Pang Xiaoyan   Feng Chen   Zhao Xinying  

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The evolution of the spin density vectors (SDVs) is studied in a strongly focused composite field. It is found that the SDVs can be spiral along the propagation axis and they are perpendicular to ys direction on the ys axis. This behavior is governed by the Gouy phase difference between the field polarization components. The 60° rotation of the spatial distribution of the transverse SDVs is also generated, which is found to be controlled by the Gouy phase difference between the field orbital angular momentum modes. Additionally, the spin density singularities are observed in the evolution of the SDVs.

       PDF全文 (下载：7)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Fang Wei   Yang Kui   Li Haiyuan  

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To balance the accuracy and efficiency in multiple-view triangulation with sequential images, a high-efficiency propagation-based incremental triangulation (INT) method, carving 3D scene point by updating the incoming feature track one-by-one without iterations is proposed. Based on the INT method, a more accurate iteration-limited incremental triangulation (ININT) method is also established with few iterations to bound the propagated errors, ensuring the accuracy of subsequent 3D reconstruction. Finally, experimental results demonstrate that the proposed methods can balance the efficiency and accuracy in different multiple-view incremental triangulation situations.

       PDF全文 (下载：2)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Deng Ming   Ren Tangxuan   Wang Jian   Chen Lin  

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Retroreflector that reflects light along its incident direction has found numerous applications in photonics, but the available metasurface schemes suffer from the issue of narrow bandwidth and/or a single angle of incidence. Here a retroreflector using double layers of achromatic gradient metasurfaces is reported, which can realize retroreflection over a continuous range of incidence angles within a wide spectral band. The first metasurface serves as a transmissive achromatic lens that performs a broadband spatial Fourier transform and its inverse, while the second metasurface works as a reflective achromatic lens that undergoes a wavelength- and position-dependent phase dispersions. Using this design strategy, a near-infrared retroreflector comprised of silicon nanopillars with the cross-sections of square pillars and square holes is numerically demonstrated, providing a high-performance retroreflection for polarization-independent incident light waves over a continuous range of incidence angles from 0 to 16° within an extremely broad wavelength range between 1.35 and 1.95 μm. The scheme herein can offer a design strategy of broadband retroreflectors, and impact numerous photonics applications.

       PDF全文 (下载：2)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Zhang ZeXin   Tian Jinrong   Xu Changxing   Xu Runqin   Cui Youshuo   Zhuang Bihui   Song Yanrong  

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Noise like pulses having pedestal of 690 fs and spike of 59.6 fs were generated in a nonlinear Yb-doped fiber amplification system. The seed source is a mode-locked Yb-doped fiber laser by nonlinear polarization rotation, and dissipative soliton pulses were obtained in it. Then the dissipative soliton pulses passed through a 7.6-m dispersive fiber to enhance the dispersion and nonlinearity. On further the dissipative soliton pulses were launched into an Yb-doped fiber nonlinear amplifier, and stable noise like pulses with a pedestal of 6.26 ps and spike of 227 fs were achieved. Finally, by a grating pair, the pedestal and spike of the noise like pulses were effectively compressed to 690 fs and 59.6 fs, respectively. To the best of our knowledge, this is the shortest pedestal demonstrated in noise like pulses operating at 1 µm.

       PDF全文 (下载：9)        Chinese Optics Letters ，2020年第18卷第12期 pp.12      

VIJAYAKUMAR   A.   Katkus Tomas   Ng Soon Hock   Juodkazis Saulius  

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Fresnel incoherent correlation holography (FINCH) is a well-established incoherent imaging technique. In FINCH, three self-interference holograms are recorded with calculated phase differences between the two interfering, differently modulated object waves and projected into a complex hologram. The object is reconstructed without the twin image and bias terms by a numerical Fresnel back propagation of the complex hologram. A modified approach to implement FINCH by a single camera shot by pre-calibrating the system involving recording of the point spread function library and reconstruction by a non-linear cross-correlation has been introduced recently. The expression of the imaging characteristics from the modulation functions in original FINCH and the modified approach by pre-calibration in spatial and polarization multiplexing schemes are reviewed. The study reveals that a reconstructing function completely independent of the function of the phase mask is required for the faithful expression of the characteristics of the modulating function in the image reconstruction. In polarization multiplexing method by cross-correlation, a partial expression was observed, while in spatial multiplexing method by cross-correlation, the imaging characteristics converged towards a uniform behavior.

       PDF全文 (下载：1)        Chinese Optics Letters ，2021年第19卷第2期 pp.02      

Liu Xu   TAN CHAOYONG   Cheng Yong   Wei Jingsong   Mengzhen Zhu   CHEN XIA   MI CHAOWEI  

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To obtain short pulse width and high peak power laser, 7 kHz sub-nanosecond microchip laser amplified by a grazing incidence double pass slab amplifier is experimentally demonstrated in this letter. We use a compact side-pumped Nd:YVO4 bounce amplifier with grazing incidence beam for achieving high gains and power extraction. Laser output power of 7.37 W at 7 kHz, 1.2 MW pulse peak power with 877 ps duration and 1.05 mJ energy, 25 pm spectral width, and near diffraction limited mode beam quality are achieved, the optical-to-optical efficiency is 18%. The laser is packaged in a volume of 356×226×84 mm3, may be used for applications such as laser altimeters and ladar systems.

       PDF全文 (下载：2)        Chinese Optics Letters ，2021年第19卷第2期 pp.02