Journals >Acta Photonica Sinica
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2019
Volume: 48 Issue 2
24 Article(s)
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Luminescent Properties and Energy Transfer of K2MgSiO4∶Eu3+, Tb3+ Phosphors
SHEN Yu-ling, WAN Ying, YE Ying, WANG Qing-ling, and Aierken·Sidike
A series of fluorescent materials K2MgSiO4∶Eu3+, Tb3+ were synthesized by the high temperature solid phase method. The phase structure and luminescent properties of the materials were characterized and studied by X-ray diffraction, photoluminescence and fluorescence lifetime. The results show that the X-ray diffractionA series of fluorescent materials K2MgSiO4∶Eu3+, Tb3+ were synthesized by the high temperature solid phase method. The phase structure and luminescent properties of the materials were characterized and studied by X-ray diffraction, photoluminescence and fluorescence lifetime. The results show that the X-ray diffraction pattern diffraction peaks of the series samples agree well with the standard card, Eu3+, Tb3+ single doping or co-doping could not change the crystal structure of K2MgSiO4 in the experimental concentration range. It can be seen from the photoluminescence spectrum of the material that the photoluminescence spectrum of Eu3+ doped K2MgSiO4 reveal a red light emission at 613 nm (5D0→7F2) with an excitation at 394 nm (7F0→5L6); With Tb3+ ion singly doped K2MgSiO4 shows a green light emission at 542 nm (5D4→7F5) with an excitation at 378 nm (7F6→5G6). When Eu3+ and Tb3+ are co-doped in the K2MgSiO4, the sample exhibits a strong characteristic emission of Eu3+, the Tb3+ emission peak is weaker, and with the increase of the concentration of Tb3+ ions, the emission of Eu3+ is obviously enhanced, while there is no significant change in the emission of Tb3+. In addition, when the Eu3+ concentration is fixed and the Tb3+ ion doping concentration is gradually increased, the fluorescence lifetime of Eu3+ increased gradually; when the concentration of Tb3+ is fixed and the Eu3+ ion doping concentration is gradually increased, the fluorescence lifetime of Tb3+ decreased gradually. These phenomena determine the energy transfer relationship of Tb3+→Eu3+ in K2MgSiO4∶Eu3+, Tb3+ fluorescent materials. This relationship improves and enhances Eu3+ red light emission in the K2MgSiO4 matrix..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 216003 (2019)
Feasibility of Satellite-borne Wind Observations of Stratosphere and Mesosphere Based on the Emission Line O19P18 of O2(a1Δg)
FENG Yu-tao, WU Kui-jun, FU Di, HAO Xiong-bo, WU Jun-qiang, FU Jian-guo, and HU Bing-liang
The main propose of this paper is to discuss the possibilities and advantages of satellite-bornelimb-viewing for wind observations of stratosphere and mesosphere based on the emission line O19P18 of O2(a1Δg)O19P18(7 772.03 cm-1). The radiative transfer model of O2(a1Δg, υ′=0)→O2(X3Σg,υ″=0) is constructed based on atmosThe main propose of this paper is to discuss the possibilities and advantages of satellite-bornelimb-viewing for wind observations of stratosphere and mesosphere based on the emission line O19P18 of O2(a1Δg)O19P18(7 772.03 cm-1). The radiative transfer model of O2(a1Δg, υ′=0)→O2(X3Σg,υ″=0) is constructed based on atmosphere model and radiative transfer theory. Furthermore, multiple scattering radiative transfer and nonlocal thermal equilibrium (non-LTE) models are taken into consideration in the simulation of spectrum from limb-viewing. The emission line O19P18 (7 772.030 cm-1) with weak self-absorption, bright radiation intensity and large spectral separation range is proved to be suitable for limb-viewing wind detection. Applying the emission line O2(a1Δg)O19P18 for wind observation gets low requirement of spectral resolution and full width of half maxima of filter, making the satellite loading much more possible to be miniaturization and stabilization. The O2(a1Δg)O19P18(7 772.03 cm-1) based Doppler asymmetric spatial heterodyne interferometer technique scheme is also proposed in this paper.The simulation of limb-viewing wind measurement by proposed scheme indicates that wind measurement precision is better than 5 m/s over an altitude range of 40 to 70 km in general. In the low precision requirement condition, the measurement range could reach lower than 40km. The research achievement of this paper could provide the low cost, high precision, independent technique approach for stratosphere and mesosphere wind measurement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 201001 (2019)
Improved Subharmonic Method for Simulation of Atmospheric Turbulence Phase Screen
LIU Tao, ZHU Cong, SUN Chun-yang, ZHANG Jing-zhi, LEI Yan-xu, and ZHANG Rong-xiang
An improved subharmonic method to generate atmospheric turbulence phase screen was introduced. The low frequency phase screen is specifically designed to quickly achieve adequately sampling in low frequency portion of power spectrum. To evaluate the accuracy of the proposed method, the phase structure function of phaseAn improved subharmonic method to generate atmospheric turbulence phase screen was introduced. The low frequency phase screen is specifically designed to quickly achieve adequately sampling in low frequency portion of power spectrum. To evaluate the accuracy of the proposed method, the phase structure function of phase screen generated by using this method is calculated and compared with the theoretical Kolmogorov structure function. The accuracy of the simulated phase screen can be improved with the increase of subharmonics. In addition, comparison between the improved subharmonic method and other four phase screen generation methods (standard fast Fourier transform method, subharmonic method, Zernike polynomials method and random mid-point displacement method) is also carried out. The comparative results show that the phase structure function for the improved subharmonic method matches very closely that of Kolmogorov turbulence theory, and it is the best one in comparison with those of other four phase screen generation methods..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 201002 (2019)
Calibration of Frequency Discriminator and Application for Doppler Lidar Based on Fiber Mach-Zehnder Interferometer
WANG Li, CHEN Kai, CHEN Xu, GAO Fei, WANG Jun, YAN Qing, YAN Wen-xiu, and HUA Deng-xin
The wind measuring sensitivity and dynamic range for Fiber Mach-Zehnder Interferometer (FMZI) based Doppler lidar are analyzed. The detection dynamic range is ±199.5 m/s and ±13.3 m/s for 0.1 m and 1.5 m Optical Path Difference (OPD). The optimal sensitivity is 2.15% with the change of wind speed of 1 m/s, coThe wind measuring sensitivity and dynamic range for Fiber Mach-Zehnder Interferometer (FMZI) based Doppler lidar are analyzed. The detection dynamic range is ±199.5 m/s and ±13.3 m/s for 0.1 m and 1.5 m Optical Path Difference (OPD). The optimal sensitivity is 2.15% with the change of wind speed of 1 m/s, corresponding to an optimal OPD of 0.45 m. The OPD error will result in retrieval wind velocity error. When the OPD is equal to 0.145 9 m or 1.088 9 m, the retrieval wind velocity error is 1.028 m/s or 0.138 m/s for 1 nm OPD error. We employed laser wavelength tuning method to determine the OPD of FMZI. The experiment has been implemented to calibrate OPD. This interferometer is used as a frequency discriminator in the lidar to detect the actual wind speed. The inversion of the wind speed is in good agreement with the coherent detection of the wind speed, which proves the correctness of the calibration detection..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 201003 (2019)
Optical Fiber Perimeter Vibration Signal Recognition Based on Multifractal Spectrum
XIONG Xing-long, ZHANG Wan-tong, FENG Lei, LI Meng, MA Yu-zhao, and FENG Shuai
To effectively identify the vibration signals of the fiber optic perimeter system, a method was presented, which combines the multi-fractal spectrum parameters with the improved probabilistic neural network. This method could avoid the shortcomings of experience threshold selecting in extracting features and smoothing To effectively identify the vibration signals of the fiber optic perimeter system, a method was presented, which combines the multi-fractal spectrum parameters with the improved probabilistic neural network. This method could avoid the shortcomings of experience threshold selecting in extracting features and smoothing factor determining in the process of pattern recognition. First of all, the existence and validity of multi-fractal in optical fiber vibration signals were examined and analyzed. Then, the multi-fractal spectrum parameters of the fiber vibration signals were calculated and extracted to form the feature vectors which could accurately describe the nonlinear and complexity of the signals. Finally, the improved probabilistic neural network algorithm was used for adaptive learning and classification to realize the identification of different optical fiber vibration signals. Four kinds of vibration signals collected from field tests were used to verify the method and the results show that the average recognition rate reaches 96.25 % and the recognition time is 1.63 s. This method is superior to the traditional probabilistic neural network algorithm in terms of correct recognition rate..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 206001 (2019)
Research and Application of FBG Monitoring Technology in Internal Prestressed Steel Strand
ZHU Wan-xu, SHEN Quan-xi, and QIN He-ying
A self-sensing steel strand is designed, which is set a spiral and slant groove on the steel strand center wire and embedded with fiber Bragg grating (FBG) sensor. Hence, the problems of lack of installation space, fragile broken which leads to low survival rate and insufficient monitoring range can be solved. The moniA self-sensing steel strand is designed, which is set a spiral and slant groove on the steel strand center wire and embedded with fiber Bragg grating (FBG) sensor. Hence, the problems of lack of installation space, fragile broken which leads to low survival rate and insufficient monitoring range can be solved. The monitoring strain of FBG sensor with groove and the strain of steel strand are analyzed theoretically. According to the theory of shear lag model of composite material, the relationship between both strains is established. A series of self-sensing steel strand are developed with different helix angle, and the tensile experiments are carried out to determine the variation of the measurement range of FBG sensor. The experimental results show that this method can effectively improve the monitoring range of FBG sensor, When the tilt angle is 30°, the strain range that can be monitored is increased by 44% compared with 0°. Owing to this technique, the prestressing tensioning construction and service of a prestressed box beam of a highway are monitored in real time by using FBG sensor, the survival rate of the sensor is 100%. The strain relationship determined by theoretical and calibration test is compared with the data of the construction tensioning and the secondary tensioning on site, and the errors are less than 5%. This technology achieve the purpose of the whole lifecycle monitoring of the internal prestressed steel strand during construction and service..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 206002 (2019)
Fusion of Infrared and Visible Images Based on Tetrolet Framework
FENG Xin
An fusion method based on joint sparse representation and improved pulse coupled neural network in tetrolet framework was proposed. The original infrared and visible images were decomposed without considering the rotation and reflection; for the low-frequency sub-band coefficients, the joint sparse representation methoAn fusion method based on joint sparse representation and improved pulse coupled neural network in tetrolet framework was proposed. The original infrared and visible images were decomposed without considering the rotation and reflection; for the low-frequency sub-band coefficients, the joint sparse representation method was used to accurately fit and fuse the low-frequency coefficients through the learning dictionary. In the high frequency subband coefficient fusion, the corresponding fusion rule was set by using the improved pulse coupled neural network, and the high frequency coefficient of the fused image was selected according to the number of firings of the neuron. The processed coefficient values were inversely transformed by tetrolet frame to obtain the final fusion result. The results show that the proposed method can effectively preserve the edge and detail features of the image to be fused, and the fusion results have better visual effects, which can enhance the observer′s ability to perceive the scene and identify important targets. It is superior to the traditional transform domain fusion method in mutual information, gradient information, structural similarity and visual sensitivity index, especially in terms of structural similarity and gradient retention, leading by 0.033 and 0.025, respectively, and has effectiveness..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 210001 (2019)
Remote Sensing Image Encryption Using Vector Operations and Secondary Image Phase Masks
LIU Yu-jia, XU Xi-ping, XU Jia-hong, JIANG Zhao-guo, and LI Yan-di
Aiming at the problem of information security in remote sensing images and color images transmission, a method aimed at encrypting color remote sensing images using vector operations and secondary image phase masks is proposed. In this encryption, the optical coherent superposition principle is used to separate and oveAiming at the problem of information security in remote sensing images and color images transmission, a method aimed at encrypting color remote sensing images using vector operations and secondary image phase masks is proposed. In this encryption, the optical coherent superposition principle is used to separate and overlay the original image into two phase plates on the three channels R, G and B, respectively. Then the dual random phase encoding in the Fresnel domain is performed using the secondary image phase masks to encrypt one of the phase plates. Finally, the Kronecker product of two random matrices is directly perform randomization on the encoded image, achieving multilevel encryption of color remote sensing images. Experimental results show that the algorithm has a high key sensitivity, and it has good robustness under Gaussian noise attack with intensity coefficient less than 0.04 and statistical analysis attack. The ciphertext can resist the chosen-plaintext attack and has stronger security than the traditional double random phase encoding algorithm. The peak signal-to-noise ratio and correlation coefficient of the decrypted remote sensing images can reach 31.92 dB and 0.988 8. This encryption method provides a new idea for the encryption of a large number of remote sensing images of the same size..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 210002 (2019)
Influence of Micro-channel Ratio of Length to Width and Radius of Curvature on Imaging of Lobster-eye Optical System
PENG Song-wu, WEI Fei, GUO Yi-hong, and YE Yi-zhong
The influence of micro-channel ratio of length to width and radius of curvature on imaging of lobster-eye optical system under the same parallel monochromatic light source condition was investigated. The results show that with the increase of the micro-channel ratio of length to width, the angular resolution becomes beThe influence of micro-channel ratio of length to width and radius of curvature on imaging of lobster-eye optical system under the same parallel monochromatic light source condition was investigated. The results show that with the increase of the micro-channel ratio of length to width, the angular resolution becomes better while the total intensity of image surface decreases gradually. When the ratio reaches 25∶1, the effective area of focused X-rays reaches the maximum value. Under same micro-channel size condition, the change of radius of curvature has less influence on angular resolution, and the larger radius brings the larger effective area, but requires larger element volume for same field of view at the same time..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 211001 (2019)
Influence of Velocity Mismatch in Infrared Point Target Detection System Based on Time Delay Integration
PAN Sheng-da, ZHAO Ming, AN Bo-wen, SU Xiao-feng, and LIN Chang-qing
The velocity mismatch would be inevitably in the push-broom imaging process based on time delay integration, which leading to a decrease in detection performance of point targets. Due to the lack of introduction of phase transfer function, the influence of the target detection performance can not be effectively analyzeThe velocity mismatch would be inevitably in the push-broom imaging process based on time delay integration, which leading to a decrease in detection performance of point targets. Due to the lack of introduction of phase transfer function, the influence of the target detection performance can not be effectively analyzed by the frequency domain methods based on modulation transfer function. In order to solve this problem, the relationship between detection performance of point targets and velocity mismatch was studied with the establishment of the mathematical model by the point spread function and line spread function of the imaging system.The result of theoretical calculation and imaging experiment shows that the expectation of point target response will drop by approximately 50% by 8-stage time delay integration, when the velocity mismatch ratio ΔV/V=25%. When the velocity mismatch ratio ΔV/V=12.5%, the expectation of point target response decrease 30%.This research could provide reference for infrared time delay integration imaging system design..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 211002 (2019)
Ultra-wide Field Infrared Binocular Vision Epipolar Constraint and Spatial Positioning
CHEN Yi-chao, LIU Bing-qi, and HUANG Fu-yu
Traditional visible light and infrared small field view positioning systems have some shortcomings, such as vulnerable to light conditions, poor environmental adaptability, and lack of visual information. In order to overcome these shortcomings, nonlinear epipolar constraint and target spatial positioning method based Traditional visible light and infrared small field view positioning systems have some shortcomings, such as vulnerable to light conditions, poor environmental adaptability, and lack of visual information. In order to overcome these shortcomings, nonlinear epipolar constraint and target spatial positioning method based on ultra-wide field infrared binocular vision system was proposed. The generalized camera distortion model was used to describe the infrared ultra-wide camera imaging process, and the binocular system distortion model of non-parallel structure was establish. And then the theoretical derivation of the nonlinear epipolar constraint equation for homonymous image points was completed. A target location algorithm for ultra-wide field infrared binocular vision system was established from the point of view of space geometry. The experimental results show that the matching search of homonymous image points, included eight target points with the distance from 1.75~8.05 m in different scenes, is reduced from two-dimensional to one-dimensional under the conditions of epipolar constraint. The matching results were brought into the solution equation of three-dimensional spatial positioning and the distance error of positioning is between 0.9% and 7.0%. The higher positioning accuracy shows the correctness of the proposed method, and verifies the spatial positioning ability and advantage of the ultra-wide field infrared binocular vision system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 211003 (2019)
Noise Estimation of Hyper-spectral Infrared Atmospheric Sounder Observations Using Principal Component Analysis
LEE Lu, QI Cheng-li, ZHANG Peng, HU Xiu-qing, and GU Ming-jian
To evaluate the noise during atmosphere observation, the imaginary part of the atmospheric complex Fourier transform spectra are taken into consideration. However, the imaginary spectrally correlated noise introduced by sampling jitters would be added to the random noise inherent to infrared detectors, which elevates tTo evaluate the noise during atmosphere observation, the imaginary part of the atmospheric complex Fourier transform spectra are taken into consideration. However, the imaginary spectrally correlated noise introduced by sampling jitters would be added to the random noise inherent to infrared detectors, which elevates the total instrumental noise floor or even exceeds the sensibility threshold. Utilizing principal component analysis technique, this correlative noise could be reconstructed and filtered out. Then the remaining noise is represented as the noise equivalent differential temperature and compared with that from the calibration target radiance. The results show that the random spectra noises from different scenes are consistent with each other, and all meet the sensibility requirments of 0.4 K, 0.7 K and 1.2 K corresponding to three spectral bands..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 212001 (2019)
Terahertz Non-destructive Testing Technology for Glass Fiber Honeycomb Composites
ZHANG Dan-dan, REN Jiao-jiao, LI Li-juan, QIAO Xiao-li, and GU Jian
The terahertz time domain waveform was optimized with double Gaussian filtered inverse filtering technology. A terahertz reflection tomography technique based on terahertz time-domain spectroscopy nondestructive testing was proposed to analyze the bonding quality of glass fiber honeycomb composites. Combined with the cThe terahertz time domain waveform was optimized with double Gaussian filtered inverse filtering technology. A terahertz reflection tomography technique based on terahertz time-domain spectroscopy nondestructive testing was proposed to analyze the bonding quality of glass fiber honeycomb composites. Combined with the characteristics of the glass fiber honeycomb composite structure, circular and trapezoidal debonding defects with different diameters were designed in the upper and lower layer of the honeycomb film. On this basis, the fabrication of the debonding defect honeycomb structure samples were completed. The proposed terahertz reflection tomography and B-scan imaging methods are suitable for the analysis of debonding defects of glass fiber honeycomb composites. Aiming at the problem of poor contrast of reflective tomography image, combined with the characteristics of terahertz time domain waveform data at the debonding defect, the defect feature time domain imaging optimization technology is used to improve the detection ability and recognition accuracy of debonding defects and realize the terahertz nondestructive testing of glass fiber honeycomb composite with its upper debonding thickness as 50 μm and lower debonding thickness as 50 μm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 212002 (2019)
Rapid Optic Axis Calibration of Bio-vision Ranging Sensors Based on Compound Eyes
YANG Yu-li, XING Qiang, YAO Jian-nan, DAI Zhen-dong, WANG Guo-jun, and XU Hai-li
Based on the processing mechanism of optic nerve and the characteristics of visual structure of biological compound eye, a ring-shaped vision sensor based on bionic compound eye with fast distance measurement function and 31 channels is built, and a bionic multi-channel fast vision distance measurement model based on lBased on the processing mechanism of optic nerve and the characteristics of visual structure of biological compound eye, a ring-shaped vision sensor based on bionic compound eye with fast distance measurement function and 31 channels is built, and a bionic multi-channel fast vision distance measurement model based on lateral inhibition neural network is established. To calibrate optic axis of ring sensors, a rapid way for optic axis calibration of muti-channel sensors based on discrete information with Gaussian distribution is proposed. The experimental results show that the relative accuracy of the left eye is increased by 20.46% and that of the right eye is increased by 9.00% in intermediate angle of view of sensor array after the calibration of optic axis of sensors. The angle measurement accuracy of more than 80% of the points in the middle evaluation area of the left and right eye is within ±0.60° with the sensor array that use 6° angle spacing. The location error of binocular real time ranging results is kept within the range of -3 mm to 10 mm under 50 mm/s velocity..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 212003 (2019)
Hydrothermal Synthesis and Studies on Photochromic Properties of Nd3+ Doped WO3 Powder
ZHOU Zhuo-rui, and ZHAO Xiu-jian
The synthesis of neodymium-doped hexagonal tungsten oxide nanopowder was reported by using sodium tungstate as the tungsten source, neodymium nitrate as the neodymium source, and potassium sulfate as the mineralizing agent. Phase composition, micro-morphology and doping content of the obtained nanopowder were studied bThe synthesis of neodymium-doped hexagonal tungsten oxide nanopowder was reported by using sodium tungstate as the tungsten source, neodymium nitrate as the neodymium source, and potassium sulfate as the mineralizing agent. Phase composition, micro-morphology and doping content of the obtained nanopowder were studied by using X-ray diffraction analysis, scanning electronic microscopyand X-ray photoelectron spectroscopy. The result shows that only neodymium-doped hexagonal tungsten oxide was obtained in the synthesized product and no impurity was found. Due to successfully intruding Nd3+ ion into the host lattice, partial tungsten ions were reduced to be pentavalent, which further resulted exciting electrons from valence band to conducting band and formation of additional photogenerated electron-hole pairs. Then the photochromic performance of nanoowder was found highly improved contributing to the increased absorbance of excitation light. The nanopowder with best photochromic property was obtained in the sample with a optimized trivalent neodymium ion concentration of 5.63%. Its change of color was estimated to be 13 times of that observed in the pure WO3..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 216001 (2019)
Study on Co-enhancement of Upconversion of β-NaYF4∶Er3+ by Surface Plasmon
HUANG Hai, LIN Lin, HUANG Li-li, FENG Zhuo-hong, ZHENG Biao, WANG Zhe-zhe, and ZHENG Zhi-qiang
β-NaYF4∶Er3+ upconversion nanoparticles were prepared by using coprecipitation method. The Ag nanocubes prepared by chemical reduction method and the Au nanorods prepared by seed-mediated growth method were doped into β-NaYF4∶2%Er3+ nanoparticles to form nano-composites, respectively. Therefore the enhancements of upcoβ-NaYF4∶Er3+ upconversion nanoparticles were prepared by using coprecipitation method. The Ag nanocubes prepared by chemical reduction method and the Au nanorods prepared by seed-mediated growth method were doped into β-NaYF4∶2%Er3+ nanoparticles to form nano-composites, respectively. Therefore the enhancements of upconversion luminescence on β-NaYF4∶Er3+ NPs were achieved through surface plasmon resonance. The enhancement was up to 4.0 times with 60 μL Ag nanocubes doped, while the enhancement was up to 7.8 times with 60 μL Au nanorods doped. Codoping Ag nanocubes and Au nanorods into β-NaYF4∶2%Er3+ nanoparticles, great enhancement of upconversion luminescence reaching 16.0 times was obtained via co-enhancement of excitation and emission..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 216002 (2019)
Study on Phase Matching Condition at Pump Depletion in Four-wave Mixing
WAN Feng, WU Bao-jian, CAO Ya-min, XING Huan-xing, and QIU Kun
The analytic method is used to analyze the range of quasi-phase matching and the evolution of the phase matching in the case of pump depletion, and the expression for the phase matching is given. The evolution process of four-wave mixing gain under pump depletion is compared to the case in small-signal approximation. IThe analytic method is used to analyze the range of quasi-phase matching and the evolution of the phase matching in the case of pump depletion, and the expression for the phase matching is given. The evolution process of four-wave mixing gain under pump depletion is compared to the case in small-signal approximation. In the case of pump depletion, with the increase of the transfer power, the linear mismatch factor corresponding to the total phase matching gradually tends to 0 and the quasi-phase matching range also becomes narrower. By determining the quasi-phase matching rang, the cascaded four-wave mixing process in wavelength division multiplex or space division multiplexing systems can be simplified for analysis. The small signal approximation model is only suitable for the case that the transfer power is far less than the pump power, and the linear mismatch factor at the total phase matching is not dependent on the length of the fiber..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 219001 (2019)
Frequency Conversion for Cubic Harmonic Generation in UV Region through 3m Point Group Crystals with Centrosymmetric Sturcture
SHI Meng-jing, LI Ren-fu, LI Bing-xuan, LIU Hua-gang, LIN Wen-shuo, PAN Jia, ZHANG Ge, and YE Ning
A simple one-step direct third-order nonlinear frequency conversion process in centrosymmetric crystals was studied, and an efficient third-harmonic generation in UV region was obtained. The expressions of phase-matching angles were determined. α-BBO crystal and the calcite crystal which both have the delocalized π bonA simple one-step direct third-order nonlinear frequency conversion process in centrosymmetric crystals was studied, and an efficient third-harmonic generation in UV region was obtained. The expressions of phase-matching angles were determined. α-BBO crystal and the calcite crystal which both have the delocalized π bond were selected in our experiment. In type-Ⅱ phase-matched, the maximal output energy was 19.3 μJ and the maximal conversion efficiency was about 1.25% at 266 nm in calcite crystal, while the value was 37.6 μJ and 2.5% in α-BBO crystal. These results indicate the feasibility of direct third-harmonic generation in UV region, the possibility of direct third-harmonic generation in deep-UV region through centrosymmetric crystals, and also demonstrated a succinct and efficient way to generate deep-UV laser and a development direction of nonlinear crystals in UV region..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 219002 (2019)
Method for Reducing Pressure Angle of Cam Curve in Zoom System
GAO Tian-yuan, WU He-long, and HAN Xu
In the design of continuous zoom optical system with mechanical compensation, in order to make the zoom system image continuously and smoothly, this paper proposes a method to reduce the cam curve pressure angle of the zoom system. By changing the equation of the zoom curve and applying the principle of dynamic optics,In the design of continuous zoom optical system with mechanical compensation, in order to make the zoom system image continuously and smoothly, this paper proposes a method to reduce the cam curve pressure angle of the zoom system. By changing the equation of the zoom curve and applying the principle of dynamic optics, the pressure angle of the fitted compensation curve has a significant decreasing trend. In the original design, the pressure of the zoom curve is 31.4°, and the maximum pressure angle of the compensation curve is greater than 50°. Using the interpolation method to change the equation of the variable magnification group to obtain a new cam curve,the maximum pressure angle of the zoom curve is less than 37° and the maximum pressure angle of the compensation curve is less than 23°. A new cam curve is obtained that satisfies the requirement that the curve pressure angle is less than 45°.The results of the actual optical system test prove the feasibility of this method. By this method, the pressure angle of the cam curve can be reduced, the actual zoom system can image continuously and clearly..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 222001 (2019)
Opto-mechanical Design of Self-calibraiton Radiometric Reference Source Prototype Based on Spontaneous Parametric Down-conversion
TANG Qi, LI Jian-jun, LI Chen, ZHAI Wen-chao, HU You-bo, and ZHENG Xiao-bing
In order to meet the requirements of ultra-high precision calibration for global climate observation and quantitative remote sensing, a prototype system based on spontaneous parametric down-conversion self-calibration radiation reference source was developed. The design was fully considered to be modular, lightweight aIn order to meet the requirements of ultra-high precision calibration for global climate observation and quantitative remote sensing, a prototype system based on spontaneous parametric down-conversion self-calibration radiation reference source was developed. The design was fully considered to be modular, lightweight and integrated. The static analysis of the key part of the detector module showed that the position of the detector's photosensitive surface was shifted by 21 μm, the photosensitive surface of the detector was 180 μm, and the diameter of the photon spot of the lens was 16 μm. The spot could be fully detected, which met the design requirements. A low-light camera was used to observe the photon spots in front of each detector, the results showed that the spot shape was regular and the size was complete. The single photon detector was used to collect the relevant photons. The eight-channel four-pair correlated photon matching peaks were drawn by the coincidence measurement, and the principle was verified. The machine structure was well designed to meet the design goals..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 222002 (2019)
Mirrors of Beam Stabilization System for Immersion Lithography
LI Mei-xuan, LI Hong, ZHANG Si-qi, GUO Ming, and FU Xiu-hua
According to the technical requirements of the immersion lithography system, the beam stabilization system was designed through eliminating the positional drift and the pointing drift of the beam by two mirrors. Based on the characteristics of deep ultraviolet materials, JGS1 was chosen as the substrate of the mirror, According to the technical requirements of the immersion lithography system, the beam stabilization system was designed through eliminating the positional drift and the pointing drift of the beam by two mirrors. Based on the characteristics of deep ultraviolet materials, JGS1 was chosen as the substrate of the mirror, and Al2O3 and MgF2 were chosen as high and low refractive index thin film materials respectively. The design and simulation analysis of high-reflection film were completed through the film design software, and the film was developed by vacuum deposition technology. The non-uniformity index of the film was ensured to be less than 0.2%by selecting the planetary fixture coating equipment and designing the specific compensation baffle. The spectrum curve and the surface microstructure of the mirror sample were tested. The results show that the developed film has a reflectance of 98.5% at 45° incidence and a scattering loss of 0.30%, which satisfies the system requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 222003 (2019)
Design and Measurement of CMOS Terahertz Thermal Detector with Gate-antenna and NMOS Transistors
LI Zi-meng, YANG Jiao, and CHEN Fei
A structure of thermal terahertz detector working at room temperature was proposed. The detector is consisted of an on-chip antenna and a temperature sensor. The antenna made of gates of the temperature sensor absorbs incident terahertz wave and converts it to Joule heat. The heat-generated temperature rise is then detA structure of thermal terahertz detector working at room temperature was proposed. The detector is consisted of an on-chip antenna and a temperature sensor. The antenna made of gates of the temperature sensor absorbs incident terahertz wave and converts it to Joule heat. The heat-generated temperature rise is then detected by the temperature sensor. The working flow of the detection can be divided into three parts: electromagnetic absorption, thermal-heat conversion and thermal-electrical conversion. Modeling and simulation of every process are presented. The simulated Antenna absorptivity is 0.897, the heat transfer efficiency is 165 K/W and the thermoelectric conversion efficiency is 1.77 mV/W. The detector is designed based on 0.18 μm CMOS technology with post-process thinning the silicon substrate to 300 μm. Its simulated voltage responsivity is 262 mV/W at 3 THz frequency, while the tested value is 148.83 mV/W under the incident power of 1mW..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 223001 (2019)
Design on the Convex Ring MIM Structure Filter Based on Surface Plasmon Polaritons
YAN Yun-fei, ZHANG Guan-mao, QIAO Li-tao, and FAN Guan-ping
A novel Metal-Insulator-Metal (MIM) structure filter was constructed by using the boundary-coupled method. The structure consists of a convex ring resonator and a waveguide. The magnetic field distribution, transmission spectra and resonance wavelength distribution of the convex ring cavity waveguide structure were obtA novel Metal-Insulator-Metal (MIM) structure filter was constructed by using the boundary-coupled method. The structure consists of a convex ring resonator and a waveguide. The magnetic field distribution, transmission spectra and resonance wavelength distribution of the convex ring cavity waveguide structure were obtained by Finite Element Method (FEM) numerical simulation. The influence of various structural parameters on the transmission characteristics of the filter is analyzed in detail.The results show that the proposed convex ring filter has narrow transmission peaks, smooth transmission spectra and other characteristics, and the minimum stopband transmission rate can reach 0.001, and the passband transmittance can reach 0.977. When the structural parameter h2 and neffis increased, the corresponding transmission spectrum undergoes a significant red shift. When the structural parameter L1 is increased, the transmission spectrum hardly changes. By adjusting and optimizing various structural parameters of the structure, the resonance wavelengths can distribute in the vicinity of 850 nm (the first communication window) and 1 550 nm (the third communication window), and can be well used in communications..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 223002 (2019)
Spontaneous Emission Characteristics of Atom near the Interface of Chiral Metamaterial and Chern Insulator
WANG Chi, ZENG Ran, HOU Jin-xin, LI Hao-zhen, LI Qi-liang, BI Mei-hua, and YANG Ya-ping
The spontaneous emission characteristics of the two-level atom near the surface of Chern insulator and chiral metamaterial medium is investigated. The matrices of the reflection coefficients of the chiral medium surface and the interface of chiral medium and Chern insulator are calculated, and the expression of the spoThe spontaneous emission characteristics of the two-level atom near the surface of Chern insulator and chiral metamaterial medium is investigated. The matrices of the reflection coefficients of the chiral medium surface and the interface of chiral medium and Chern insulator are calculated, and the expression of the spontaneous decay rate of the two-level atom in this environment is obtained according to the dyadic Green's function. The atomic spontaneous emission under the influence of the characteristic parameters of the chiral medium and Chern insulator is numerically analyzed. The spontaneous decay rate of the dipoles parallel and perpendicular to the interface is discussed respectively, and the spontaneous emission in the radiation mode and the evanescent mode is analyzed respectively. The results show that the spontaneous decay rate of atoms near the interface of the chiral medium is enhanced compared with the common dielectrics due to the presence of chiral parameters. Under the influence of Chern insulator, the spontaneous emission of atoms near the interface is conspicuously inhibited, and for the larger chiral parameter, the suppression effect of the Chern insulator is more significant..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 2, 227001 (2019)
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