Niu Yunfei   Yang Lei   dongjie guo   Chen Yan   Li Xiaoyang   Zhao Gang   Hu Xiaopeng  

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Abstract: We report efficient generation of 671-nm red light based on quasi-phase-matched second harmonic generation of 1342 nm in LiNbO₃ waveguides. The design method and fabrication process of the high-quality annealed proton-exchanged periodically poled channel waveguides were presented. Continuous-wave 1.71 mW red light was obtained with a single-pass conversion efficiency of 47%·W^-1·cm^-2, which is 88% that of the theoretical value. While for 1 mW quasi-continuous laser input, the conversion efficiency reached up to 60%. Our results indicate that annealed proton-exchanged periodically poled LiNbO₃ waveguide is promising for high-efficiency and low power consumption nonlinear generation of visible light.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Hu Wei   Zheng Zhi-gang   Peng Chenhui  

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Soft-matter photonics (Soft Mattonics) is an emerging and active area that has attracted widespread attention in recent years. Compared with solid materials, soft matters exhibit inherent advantages such as excellent adjustability, high flexibility, scalable size, ease of manufacture, and environmental adaptation. This special issue focuses on various interesting optical properties and fantastic photonic applications of soft matters including different liquid crystal phases, stimuli-responsive polymers, and even silks. This special issue aims to present the impressive progresses on soft matter photonics and promote developments of related applications.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第8期 pp.08      

Wang Chaofan   Li Guoqiang   Hu Fangchen   Zhao Yiheng   Jia Junlian   Zou Peng   Lu Qiuyi   Chen Jiang   Li Zhongya   Chi Nan  

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Visible light communication (VLC) shows great potential in Internet of Vehicle (IOV) applications. A single-input multi-output (SIMO) visible light communication (VLC) system for Vehicle to Everything (V2X) is proposed and demonstrated. A commercial car headlight is used as transmitter. With a self-designed 2×2 PIN array, 4 independent signals are received and equalized by deep-neural-networks (DNN) post-equalizers respectively. Maximum-ratio combining (MRC) brings signal-noise ratio (SNR) and data rate gain. The transmission data rate reaches 1.25Gb/s at 1m and exceeds 1Gb/s at 4m. To the best of our knowledge, it is the first-time demonstration of beyond 1Gb/s employing a commercial car headlight.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Zhang Tianqi   Wang Mudong   Xue Yang   Xu Jinlong   Xie Zhenda   Zhu Shining  

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We demonstrated the efficient Plasmon-induced nonlinear absorption of liquid metal GaInSn nanospheres prepared by a facile liquid-phase method. With GaInSn as saturable absorbers, passively Q-switching operation was obtained at both 1.3 and 2 μm. The pulse width of 32 ns was achieved at 1.3 μm with repetition rate of 44 kHz, single pulse energy of 51.9 μJ and output power of 425 mW. Meanwhile, 510 ns and 92 kHz pulses with energy of 36.1 μJ and output power of 2.48 W were obtained at 2 μm. This work provides the potential of liquid metal for improving metal functions and flexible optical devices.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Peng Mian   Bai Li  

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Nonsequential double ionization (NSDI) of noble gas atoms in counter-rotating two-color circularly polarized (CRTC) laser fields is investigated. A scaling law is concluded by qualitative and quantitative comparing the momentum distributions of two electrons from NSDI in CRTC laser fields for different atoms with different parameters. The scaling law indicates that the momentum distributions from an atom driven by CRTC laser frequency ω1, ω2 and laser intensity I are the same as that from another atom irradiated by CRTC laser frequency kω1, kω2 and laser intensity I×k^3. This study can provide an avenue to research of two-color laser field ionization.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Khan Muhammad   Khan Muhammad Usman   Zhao Yongpeng   Zhao Dongdi   Cui Huaiyu   Cao Ziyue   An Bo   Zhang Fefei  

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In this paper, we firstly demonstrated the influence of prepulse current and delay time on the intensity of a discharge pumped Ne-like Ar soft X-ray laser operating at 46.9nm laser with 4.8mm by employing alumina capillary having an inner diameter of 4.8mm. Specifically, the delay time was changed from 8 to 520µs in small intervals. The predischarge current was increased from 25A to 250A through small steps while keeping the main discharge current constant. Usually, a small predischarge current is applied to Ar-filled capillary to attain a plasma column having sufficient preionization before the injection of the main current. The predischarge current of 140A was declared as the best current to obtain lasing with 4.8mm diameter capillary. The laser spots were captured at best time delays for the predischarge currents of 25, 45, 80, 140 and 250A which support the experimental results. We observed that by applying the predischarge current of 140A, the laser spot exhibits small divergence, higher symmetry, and uniformity, which is clear evidence of strong amplification. The laser spot obtained at 140A is cylindrically symmetric and have well structure than those reported by all other groups in the literature. Hence, the laser spot indicates that the laser beam is highly focusable and beneficial for 46.9nm laser application. Results of this paper might open a new way to enhance applications of 46.9nm capillary discharge soft X-ray laser.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Li Gongqing   Duan Xiaofeng   Huang Yongqing   Liu kai   Ren Xiaomin  

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We proposed a method to form a flat transmitted serrated-phase high-contrast-index subwavelength grating (HCG) beam splitter (SP-HBS) for all dielectric materials which is to alternately arrange two kind of grating bars with a phase difference of π. Comparing to the typical linear-phase HCG beam splitter (LP-HBS) which consist of two symmetrical deflecting grating, the SP-HBS is extensible in size, can achieve excellent splitting abilities regardless of normal incidence or small-angle oblique incidence with large deflection angles and higher diffraction efficiency, lower energy loss and higher tolerance of fabrication accuracy. Furthermore, the incident light can be split in half at any part of the SP-HBS, and the output beams of light maintain the original shape. In this paper, we designed an SP-HBS with a 44.8° deflection angle and a 90.28% transmissivity.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Zhou Heng   Gao Chunqing   Fu Shiyao   Zhai Yanwang   Zhang Jianqiang  

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We experimentally demonstrated an approach to generate arbitrary total angular momentum (TAM) states by using two liquid crystal devices. Photons’ TAM, the sum of spin and orbital angular momentum (SAM/OAM) under paraxial ap-proximation, have found many applications in optics, and attached increasing attention in recent years. Our approach is based on the orthogonality of two eigen SAM components, that arbitrary TAM states will be produced through encoding different holograms in one system. The comparison with theoretical predications yields excellent agreement, including both separable state and non-separable state. The proposed scheme takes a step forward for generating complex structured fields, and also broaden its application to various fields like laser processing, large capacity data-transmission and so on.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Fang Yuwei   Cheng Junjie   Wang Shengbo   Gu Chun   Zou Gang   Ming Hai   Xu Lixin  

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A range-extended acidity detector based on Nile red was designed and analyzed in this work. In light of the good lasing property and solvatochromism characteristic of Nile red/ethanol solution, we have obtained laser spectra of sulfuric acid in different concentrations doped in this substrate. Moreover, to expand the acidity detection range, we proposed a tandem cuvette system containing Rhodamine 6G/ethanol and Nile red/ethanol. Consequently, the detection range could be enlarged from 26 nm to 40 nm, not only by the wavelength peak but also by the intensity ratio of dual-wavelength laser output. In addition, by changing the detection and substrate material the whole detection range could be expanded, and therefore a wide range of applications in polarity and acidity detection could be implemented via this method.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

ZENG Chunhong   Lin Wenkui   He Tao   Zhao Yukun   Sun Yuhua   Cui Qi   Zhang Xuan   Lu Shulong   Zhang Xuemin   Xu Yameng   Kong Mei   Zhang Baoshun  

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A monolithic integrated ultraviolet-infrared (UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating GaN nanowire array on silicon substrate with monolayer graphene. The device detects ultraviolet and infrared lights by different mechanisms. The ultraviolet detection is accomplished by the forbidden band absorption of GaN, and the infrared detection is realized by the free electron absorption of graphene. At peak wavelengths of 360 nm and 1540 nm, the detector has responsibilities up to 6.93 A/W and 0.11 A/W, detection efficiencies of 1.23×10¹² cm·Hz^1/2W^-1 and 1.88×10¹⁰ cm·Hz^1/2W^-1, respectively, and a short response time of less than 3 ms.

       PDF全文 (下载：13)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Li Dongdong   Mo Jianye   Wang Chong   Liu Wei   Ge Haibo   Han Dongdong   Hao Aihua   Chai Baoyu   She Jianbo  

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Li ions affect the upconversion efficiency by changing the local crystal field of luminescent center. Herein, in order to improve the upconversion efficiency of NaYF4:Yb3+/Eu3+, a series of NaYF4:Yb3+/Eu3+ micro-particles with different Li+ doping concentration were synthesized by hydrothermal synthesis method respectively. Firstly, the structure and morphology of NaYF4:Yb3+/Eu3+ upconversion micro-particles (UCMPs) with different doping concentration were analysized by X-ray diffraction and scanning electron microscope (SEM). SEM results show that the UCMPs are not only highly crystallized, but also hexagons with different Li+ concentration of NaYF4:Yb3+/Eu3+. X-ray diffraction shows that the crystal field around Eu3+ changes with the increase of Li+ concentration. Then the fluorescence spectrum of NaYF4:Yb3+/Eu3+ was studied under the irradiation of 980nm laser. The results show that the fluorescence intensity of NaYF4:Yb3+/Eu3+ with 2% Li+ is the strongest, which is twice stonger the NaYF4:Yb3+/Eu3+ without Li+. Finally, the fluorescence imaging analysis of NaYF4:Yb3+/Eu3+ with 2% Li+ concentration was carried out. The upconversion micro-particles are used to screen printing to evaluate the imaging effect on different sample surfaces. The results show NaYF4: Yb3+/Eu3+ (with 2% Li+) have great application prospects in anti-counterfeiting recognition.

       PDF全文 (下载：12)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Feng Zhao   Yu Jianjun   Li Jingling  

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We proposed and demonstrated a new scheme for simultaneous generation independent wired and wireless signals employing an integrated polarization multiplexing modulator. In the experimental system, a 10 Gb/s wired signal is imposed on the original optical carrier with one polarization, while a wireless signal with bit rate lager than 4 Gb/s is carried on the generated millimeter wave with 76.44 GHz which has the polarization is orthogonal to the wired signal. The dual services are successfully delivered over a 15km standard single mode fiber, while the power penalties of the wired and wireless signals are around 0.4 dB and 1.5 dB, respectively.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Fan Li   Wang Xiaoyu   Zhao Xiaodong   Wang Jianhui   Shen Jun   Fan Huibo   Zhu Jun   Shen Mingya  

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A continuous-wave Nd:YVO4/BaWO4 Raman laser generating simultaneous multi-wavelength 1st-Stokes and 2nd-Stokes emissions is demonstrated for the first time. Investigations concerning different pump spot sizes and crystal lengths were conducted to improve thermal effect and pump absorption. Three 1st-Stokes lasers at 1103.6, 1175.9, 1180.7 nm and two 2nd-Stokes lasers at 1145.7, 1228.9 nm are obtained simultaneously using the Raman shifts of 925 cm-1, 332 cm-1 in BaWO4 and 890 cm-1 in YVO4. At the incident pump power of 23.1 W, 1.24 W of the maximum Raman output power is achieved, corresponding to an optical conversion efficiency of 5.4%. We also present a theoretical analysis of the competition between different Stokes lines.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Zhou Changhe  

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It is well-known that Chirped Pulse Amplification (CPA) technique is awarded by 2018 Nobel Physical Prize to Mourou and Strickland. The compression and stretch using gratings is the essence of CPA technique for amplifying femtosecond laser pulse. It seems less introduced to the public that there are also other structures for compression and stretching of femtosecond laser pulses using other diffractive gratings, such as doubled-density gratings, deep-etched gratings. Therefore, from the view of diffractive optics, CPA technique is reviewed with different approaches and experimental implementations which are not only useful for a more comprehensive retrospective overview of CPA, but also for the prospective of the CPA technique in the future.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第11期 pp.11      

Tong Jiang   Si Gao   ZhenNan Tian   Zhang Hanzhuang   LiGang Niu  

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A 400 nm femtosecond laser was used to ablate the surface of HPHT diamond, and the subwavelength surface microstructures with a period of 100 nm were achieved. A variety of micro-nano composite surface structures were prepared by changing the polarization direction and laser scanning direction. By dynamically adjusting the laser polarization and the laser scanning tracks, a maskless direct writing fabrication of micro-nano complex structures was realized. The micro-nano patterning on ultra-hard and super-stability diamond provides a new idea for the preparation of friction reducing surfaces, nano imprint transfer templates, SERS test substrates, and micro-nano optical structures.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Wang Xinkun   Xiong Kedi   Jin Xin   Yang Sihua  

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The previous methods to measure flow speeds by photoacoustic microscopy solely focused on either the transverse or the axial flow component, which did not reflect absolute flow speed. Here we present absolute flow speed maps by combining Doppler bandwidth broadening with volumetric photoacoustic microscopy. Photoacoustic Doppler bandwidth broadening and photoacoustic tomographic images were applied to measure the transverse flow component and the Doppler angle, respectively. Phantom experiments quantitatively demonstrated that a range of 55º to 90º Doppler angle, and 0.5 to 10 mm/s of flow speed can be measured. This tomography-assisted method provides the foundation for further measurement in vivo.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Chang Hongxiang   Xi Jiachao   Su RongTao   Ma Pengfei   Ma Yanxing   Zhou Pu  

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Coherent beam combining (CBC) of 60 fiber lasers by using stochastic parallel gradient descent (SPGD) algorithm has been demonstrated. The functions of pinhole(s) on the power distributions in the far-field have been systematically simulated on both in-phase and out-of-phase modes. Only one photoelectric detector was used to detect the combined power in the far-field central lobe of in-phase mode state. When the phase controller was in closed loop, the contrast of the far-field intensity pattern was as high as ~97% with residual phase error of ~λ /30, and ~34.7% of the total power was contained in the central lobe.

       PDF全文 (下载：5)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Liu Chenxi   Liu Kun   Wang Xiaorun   Wu Luyan   Li Jian   Wang Qin  

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Nonlocal correlations observed from entangled quantum particles imply the existence of intrinsic randomness. Normally, local projective measurements performed on a two-qubit entangled state can only certify one-bit randomness at most. While non-projective measurement can certify more randomness with the same quantum resources. In this paper, we carry out an experimental investigation on quantum randomness certification through a symmetric, informationally complete, positive operator-valued measurement, which in principle can certify the maximum randomness through an entangled qubit. We observe the quantum nonlocal correlations that are close to the theoretical values. In the future, this work can provide a valuable reference for the research on the limit of randomness certification.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Sun Fei   Liu Yichao   Yang Yibiao   Chen Zhihui   He Sailing  

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A novel way to design arbitrarily-shaped retro-reflectors by optic surface transformation is proposed. The entire design process consists of filling an optic-null medium between the input and output surfaces of the retro-reflector, on which the points have 180 degree reverse corresponding relations. The retro-reflector can be designed to be very thin (a planar structure) with high efficiency. The effective working angles of our retro-reflector are very large (from -80 degrees to +80 degrees), which can in principle be further extended. Layered metal plates and zero refractive index materials are designed to realize proposed retro-reflector using for a TM polarized beam.

       PDF全文 (下载：7)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Chen Xi   Zhou Ciming   Fan Dian   Qian Li   Pang Yandong   Wei Cong   Zhao Chenguang   Liang Sijing   Li Yuxiao  

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We propose a novel modified frequency-shifted interferometer (MFSI) where a Mach-Zehnder interferometer (MZI) is added in order to obtain wavelength information. We use the Hilbert transform(HT) to extract the wavelength information from the phase of the interference pattern and construct the relationship between phase and wavelength. The laser wavelength measurement experiment is used to verify the compound interferometer.Experimental results demonstrated that our method could obtain the wavelength from the phase, which is of great significance for demodulation Fiber Bragg Grating( FBG) based on frequency-shifted interferometer (FSI).

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Zhang Hai   Shang Jianyu   Liu Xiujuan   Wang Feiru   Sun weimin   Liu Yongjun  

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This paper presents a new type of optical fiber probe used to detect temperature, whose structure is very simple. The optical fiber probe is filled with cholesteric liquid crystals (CLCs) whose reflected light varies with temperature. The experimental results show that the proposed sensor can achieve a temperature sensitivity of 5.64 nm/°C. The sensor has the advantages of simple structure, low cost and easy to mass manufacture. Its size is very tiny (the tapered structure, 125 μm in maximum diameter and <300 μm in length) and easy to integration and measure. Meantime, the tapered structure of the probe is also ideal for measuring small samples such as cells and microfluidic channel, which will be a promising candidate for monitoring temperature fluctuations in small spaces.

       PDF全文 (下载：5)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Qu Zhiyuan   Lu Ping   Li Yujian   Fu Xin   Zhang Wanjin   Liu Deming   Zhang Jiangshan  

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In this letter, a low-frequency acoustic sensor based on extrinsic Fabry-Pérot (FP) interferometer with silicon nitride (Si3N4) membrane is demonstrated. Using micromachining techniques, the 800 nm thick Si3N4 membrane is deposited on a 8 mm×8 mm×400 μm silicon (Si) substrate. All the assembly procedures of the sensor are focused on the substrate to avoid any damage to the membrane itself, compared to general membrane transfer methods. The frequency response of the proposed sensor is discussed theoretically and experimentally demonstrated. The sensor performs an excellent flat response to the tested acoustic frequency range of 1 Hz to 250 Hz. The phase sensitivity is around -152 dB re. 1 rad/μPa with sensitivity fluctuation less than 0.8 dB. The frequency response characteristic shows a promising potential of the sensor in low frequency acoustic signal sensing applications.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Wu Jiaqi   Zheng Yinhui   Zeng Zhinan   Li Ruxin  

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High-order harmonic generation originated from zigzag graphene nanoribbons (ZGNR) induced by intense laser pulses is investigated theoretically. During the interaction between the intense mid-infrared laser with the ZGNR, we find that localized edge states mainly contribute to the generation of the low-order harmonics, while cutoff harmonics result from the other confined states. Our result shows that the edge state effect of ZGNR with narrow width can enhance the conversion efficiency of low-order harmonics, rather than the higher harmonics extended to the cutoff region.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Wang Cong   zhao mengfei   Hao Qianqian   Zou Zhengting   Fan xiuwei   Liu Jie   su liangbi  

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We report on laser diode (LD) pumped passively Q-switched Yb,Gd:SrF₂ lasers with high single-pulse energy for the first time. In addition, a stable Q-switched laser based on a Cr⁴⁺:YAG saturable absorber was demonstrated. The maximum output power of Q-switched obtained was 495 mW, with a pulse width and pulse repetition rate of 233 ns and 1.238 kHz, respectively. The corresponding single-pulse energy and the peak power were as high as 400 µJ and 1.714 kW. The laser was operated at a TEM₀₀ mode, and the beam quality was near-diffraction-limited.

       PDF全文 (下载：12)        Chinese Optics Letters ，2020年第18卷第10期 pp.10      

Chen Yung-Fu   Lee C. C.   Wang C. H.   Hsieh M. X.  

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The study of structured laser beams has been one of the most active fields of research for decades, particularly in exploring the laser beams with orbital angular momentum. The direct generation of structured beams from laser resonators is deeply associated with the formation of transverse modes. The wave representations of transverse modes of spherical cavities are usually categorized into Hermite-Gaussian (HG) and Laguerre-Gaussian (LG) modes for a long time. Enormous experimental results have revealed that the generalized representation for the transverse modes is the Hermite-Laguerre-Gaussian (HLG) modes. We make a detailed overview for the theoretical description of the HLG modes from the representation of SU(2) in the Jordan–Schwinger map. Furthermore, we overview how to derive the integral formula for the elliptical modes based on the Gaussian wave-packet state and the inverse Fourier transform. The relationship between the HLG modes and elliptical modes is linked by the quantum Fourier transform. The most striking result is that the HLG modes can be exactly derived as the superposition of the elliptical modes without involving Hermite and Laguerre polynomials. Finally, we discuss the application of the HLG modes in characterizing the propagation evolution of the vortex structures of HG beams transformed by astigmatic mode converter. This overview certainly provides not only a novel formula for transverse modes but also a pedagogical insight into quantum physics.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第9期 pp.09      

SHAO DIXIANG   Chen Yao   Zhou T.   Zhang R.   FU ZHANGLONG   Zhuang Songlin   Cao Juncheng  

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Optical frequency combs, which are generated by the cascade of a phase modulator and a Mach-Zehnder intensity modulator, are used as a polychromatic signal source in the terahertz imaging system to improve imaging quality. Interference effect caused by the monochromatic wave has been greatly suppressed. The required optical power in the presented system is as low as ~30% of that in the system using the Er-doped fiber amplifier as source, which can reduce cost and protect photodiodes from damage. This work provides an effective, low power consumption, low cost, and easy way to realize terahertz imaging with high quality, and can be used in the future security inspection.

       PDF全文 (下载：4)        Chinese Optics Letters ，2019年第17卷第4期 pp.04      

Yan Dongyu   Liu Bowen   Chu Yuxi   Song Huanyu   Chai Lu   Hu Minglie   Wang Qingyue  

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We report a hybrid femtosecond laser system based on a femtosecond Yb-doped fiber laser and an Yb:KGW regenerative amplifier. To match the central wavelength of the seed source, an Yb:KGW crystal is used in the regenerative amplifier for Np-polarization. We study and optimize the dynamics of nonlinear amplification to alleviate the gain narrowing effect. With optimization, the system can output 270-fs pulses with 21-μJ pulse energy at a 60-kHz repetition rate.

       PDF全文 (下载：1)        Chinese Optics Letters ，2019年第17卷第4期 pp.04      

zhang yanjun   Li Yunchao   Hu Xuwen   Zhang Lu   Liu Zhaojun   Zhang Kaifang   Mou Shihao   Zhang Shougang   Yan Shu-Bin  

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As the key part of chip-scale atomic clocks (CSACs), the vapor cell directly determines the volume stability and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manufacture of corresponding vapor cells. However, their micro-fabrication is challenging. This overview presents the research development of vapor cells of the past few years and analyzes the shortages of the current preparation technology. By comparing several different vapor cell preparation methods, we successfully realized the micro-fabrication of vapor cells using anodic bonding and deep silicon etching. The microelectromechanical system (MEMS) fabrication process is presented in detail. It is simple and avoids weak bonding strengths caused by alkali metal volatilization during anodic bonding under high temperatures. Finally, the vapor cell D2 line was characterized via optical absorption resonance. According to the results, the proposed method is suitable for CSAC.

       PDF全文 (下载：6)        Chinese Optics Letters ，2019年第17卷第4期 pp.04      

Sun Han   wang Lan   Zhang Yaxin   Liang Shixiong   Han Jiaguang   Lan Feng   Zhou Xinlan   Yang Ziqiang  

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This paper presents a double layer structure combined with cracked cross meta-surface and grating surface to realize arbitrary incident linear THz wave polarization conversion. The arbitrary incident linear polarization THz wave will be induced the same resonant modes in the unit-cell, which results in polarization conversion insensitive to the linear polarized angel. Moreover, the zigzag-shaped resonant surface current leads to a strong magnetic resonance between the meta-surface and gratings, which enhanced the conversion efficiency. The experimental results show more than 70% conversion rate can be achieved under arbitrary linear polarized within a wide frequency band. Moreover, around 0.89THz nearly perfect polarization conversion is realized.

       PDF全文 (下载：5)        Chinese Optics Letters ，2019年第17卷第4期 pp.04      

Gong Dejing   Yuan Yinquan   Liang Lei   Yang Minghong  

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Using theoretical simulations for optical fiber surface plasmon resonance (SPR) sensor and prism based SPR sensor coated with negative permittivity material (NPM), we investigated the effect of the permittivity of NPM on the transmitted spectrum of optical fiber SPR sensor and the reflected spectrum of prism based SPR sensor, and then obtained optimum permittivity of the NPM which can excite the sharpest SPR spectrum in white light region (400-900 nm).

       PDF全文 (下载：6)        Chinese Optics Letters ，2019年第17卷第4期 pp.04