Journals >Acta Photonica Sinica
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2019
Volume: 48 Issue 8
24 Article(s)
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Convolution Interpolation for Division of Focal Plane Polarimeter
WU Chen-qi, ZHANG Ran, FAN Yuan-yi, and CHU Jin-kui
In order to reduce the effect of resolution reduction and mismatch between units caused by traditional interpolation method on division of focal plane polarimeter, a method of polarization information based on convolution interpolation was proposed. The labeling and convolution interpolation method was studied to extraIn order to reduce the effect of resolution reduction and mismatch between units caused by traditional interpolation method on division of focal plane polarimeter, a method of polarization information based on convolution interpolation was proposed. The labeling and convolution interpolation method was studied to extract the polarized image, thus to compute the polarization. Then, the detection system was calibrated by least square method. After calibration, the error of degree of polarization is less than 2.5% and error of angle of polarization is less than 0.25°. Finally, the proposed interpolation method was used to image in different occasions by changing differnet detectors and micro polarization arrays. The exprimental results show that the proposed method can effectively reduce the effect of resolution reduction and be well adapted to the modular division of focal plane polarimeter..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 804001 (2019)
Nonlinearity Characteristic Modeling and Correction of CCD Spectroradiometer
LIU Li-ying, LI Ye, ZHENG Feng, ZHANG Guo-yu, XU Yi-gang, and YANG Li-yan
The experimental and modelling research on the parameter-dependence nonlinearity of two key parameters (integration time and responsed gray level) of the CCD detector was carried out by using the self-developed CCD spectroradiometer. By giving the CCD′s characterization function of differential nonlinearity, the nonlinThe experimental and modelling research on the parameter-dependence nonlinearity of two key parameters (integration time and responsed gray level) of the CCD detector was carried out by using the self-developed CCD spectroradiometer. By giving the CCD′s characterization function of differential nonlinearity, the nonlinear correction was achieved for automatic integration time adjustment measurement of CCD spectroradiometer in multi-scale on the model function. The response characteristics of two-parameter adjustment were tested by the laser beam incidence, and the nonlinear characteristics of CCD photoelectric conversion were analyzed. The data coordinates is reconstructed according to the structural features of the data sets curves, and the fitting model of nonlinear change relationship with the dependent parameters of CCD is built in the new representation coordinates. The results show that, in the multi-scale range, the model can describe the precise functional relationship of the nonlinear deviation caused by CCD spectroradiometer through two parameters, that is to say, the precise quantitative characterization of the two-parameter correlation nonlinear deviation of CCD photoelectric conversion is achieved. The comparison between the response value after nonlinearity corrected by the fitting model and the monitoring value of power meter shows that the model can effectively reduce the nonlinearity deviation to less than ±2%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 804002 (2019)
Design on Global Imaging Mode Based on Electronic Rolling Shutter CMOS
SONG Ke-xin, JIA Xue-zhi, LI Ji, and ZHANG Hong-zhi
In order to eliminate the influence of rolling shutter on image quality in higher speed mapping by a CMOS airborne digital camera, the combination imaging mode of matrix array CMOS and high speed central mechanical shutter is emphatically studied based on CMOS imaging principle. The forward motion model and Signal-to-NIn order to eliminate the influence of rolling shutter on image quality in higher speed mapping by a CMOS airborne digital camera, the combination imaging mode of matrix array CMOS and high speed central mechanical shutter is emphatically studied based on CMOS imaging principle. The forward motion model and Signal-to-Noise Ratio (SNR) model of matrix array CMOS resolution imaging system based on the combination imaging mode are proposed and the existence of the corresponding range of exposure is proved under the condition of suitable forward motion and SNR of the airborne digital camera. A small-sized electric and exposure controlled accurately high speed central mechanical shutter is designed with the shortest exposure (1/2 000 s) and the highest efficiency (80%). Finally, the correctness of the right range of exposure is verified by the experimental results of the radiation calibration of an airborne digital camera based on a domestic CMOS image sensor. The experimental data indicates that the parameter proven of combination imaging mode is right and the camera's dynamic MTF at Nyquist frequency (91 lp/mm) is 0.21 which meets the practical application requirement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 804003 (2019)
Temperature and Strain Sensing Mechanism in Polarization Maintaining Fiber Based on Brillouin Dynamic Grating
XU Zhi-niu, ZHAO Li-juan, CHEN Fei-fei, CHE Xiao-xia, GUO Wen-han, and WANG He-qing
The temperature and strain sensing mechanisms based on Brillouin dynamic grating in polarization-maintaining fiber are explored. Based on the transmission characteristics of two orthogonal polarization axes of polarization-maintaining fibers, the relationships between the wavelength, the wavelength difference, the beatThe temperature and strain sensing mechanisms based on Brillouin dynamic grating in polarization-maintaining fiber are explored. Based on the transmission characteristics of two orthogonal polarization axes of polarization-maintaining fibers, the relationships between the wavelength, the wavelength difference, the beat length of Brillouin dynamic grating, and temperature and strain in fiber are investigated. The results reveal that the logarithm of the wavelength is nearly linear with the fiber temperature, and the relative change in the wavelength are linear with the strain in the fiber. The difference in wavelength between two-axes and the reciprocal of the beat length is approximately linear with the temperature and strain. This paper points out potential research directions for the polarization-maintaining fiber distributed temperature and strain sensing based on Brillouin dynamic grating..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 806001 (2019)
Leakage Bag Detection Technology of Bag Filter Based on Phase-sensitive Optical Time Domain Reflectometry
LIU Xu-an, LI Jun, SHI Bo, DING Guo-shen, TANG Yu-quan, DONG Feng-zhong, and ZHANG Zhi-rong
A distributed optical fiber sensing system based on phase sensitive optical time domain reflectometer was used to monitor the filter bag in the dust collector in real time. The positioning of the filter bag in the dust collector is realized by designing the laying mode of the optical fiber in the dust filter bag. The oA distributed optical fiber sensing system based on phase sensitive optical time domain reflectometer was used to monitor the filter bag in the dust collector in real time. The positioning of the filter bag in the dust collector is realized by designing the laying mode of the optical fiber in the dust filter bag. The optical fiber vibration signals in six types of damaged bags are collected, and the optical fiber vibration signals in these bags are also collected when they are not damaged. The information entropy and correlation coefficient of the optical fiber vibration signal in the filter bag are calculated by wavelet packet decomposition method and the two parameters are combined to form a two-dimensional characteristic parameter. The characteristic difference between the optical fiber vibration signal in the non-damaged bag and the optical fiber vibration signal in the damaged bag under different two-dimensional characteristic parameters is analyzed. The back propagation neural network is trained with the type 3 filter bag signal feature samples as the training samples, and then the six types of filter bag signal feature samples are identified. The results show that the method has higher recognition stability for the six types of filter bags. And the average recognition rate can reach 96.2%, 88.7%, 98.4%, 98.5%, 98.5%, 98.5%, respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 806002 (2019)
Optimization Design of Fiber Bragg Grating Two-dimensional Accelerometer Based on Flexure Hinge
WANG Yun, DAI Yu-tang, LIU Wen-min, and WEI Yu
In order to realize the vibration monitoring in two directions of the surface, a fiber Bragg grating bi-directional accelerometer is designed based on the circular flexure hinge. First, the theoretical formulas of its resonant frequency and sensitivity are derived. Then, based on the theoretical formulas of circular hiIn order to realize the vibration monitoring in two directions of the surface, a fiber Bragg grating bi-directional accelerometer is designed based on the circular flexure hinge. First, the theoretical formulas of its resonant frequency and sensitivity are derived. Then, based on the theoretical formulas of circular hinge stiffness, the empirical formulas of hinge stiffness are derived and verified. The mathematical model of the sensor is optimized by MATLAB, and the size parameters are obtained when the sensitivity of the sensor reaches the maximum as the work needs are satisfied. The experimental results show that the resonant frequency is about 368 Hz, the sensitivity is about 107.3 pm/g, and the transverse anti-interference degree is around 4.8%. The error between the theoretical value and the actual value of the resonant frequency and sensitivity are -4.2% and 7.0% respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 806003 (2019)
Hydrogen Sensing Characteristics of Pd-Ag Composite Film Micro-structured Grating Fiber with Different Silver Content
ZHOU Xian, YANG Mo, MING Xing-zu, WU Guo-xiu, ZHANG Wen, and DAI Yu-tang
The effect of Pd-Ag alloy atomic ratio composite films on the hydrogen sensing properties of microstructured Fiber Bragg Grating (FBG) was studied. The spiral microstructures were fabricated on fiber cladding using femtosecond laser. The Pd-Ag alloy films with different atomic ratio prepared by magnetron sputtering werThe effect of Pd-Ag alloy atomic ratio composite films on the hydrogen sensing properties of microstructured Fiber Bragg Grating (FBG) was studied. The spiral microstructures were fabricated on fiber cladding using femtosecond laser. The Pd-Ag alloy films with different atomic ratio prepared by magnetron sputtering were coated on the surface of spiral microstructured FBG. A novel microstructured FBG hydrogen sensor with optimized Pd-Ag alloy ratio was developed. The Pd-Ag thin films were characterized and analyzed by scanning electron microscope and energy dispersive spectroscopy. The hydrogen sensing of three kinds of FBG probes with different Pd: Ag atomic content (Pd∶Ag=2∶1, 4∶1, 6∶1) was tested. At room temperature, the probe with Pd4-Ag1 film has the best hydrogen sensing performance. The microstructured probe with Pd-Ag atomic ratio of 2∶1 has the fastest response speed but the lowest sensitivity. The wavelength shift of the spiral micro-structured sensor towards 4%H2 is 107 pm. Compared with the same type of FBG hydrogen sensor, it has higher sensitivity and faster response time..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 806004 (2019)
Adaptive Phase Unwrapping Method Based on Geometric Constraint
LI Wen, CAI Ning, LIN Bin, and CAO Xiang-qun
A method of unwrapping phase by the spatial geometric constraints of the camera and projector is proposed. This method only needs to calibrate the structured light measurement system without conventional temporal or spatial phase unwrapping. The approximate height information of the object is obtained by projecting oneA method of unwrapping phase by the spatial geometric constraints of the camera and projector is proposed. This method only needs to calibrate the structured light measurement system without conventional temporal or spatial phase unwrapping. The approximate height information of the object is obtained by projecting one-period fringes to determine virtual depth plane, and at the virtual plane z0min, the minimum absolute phase map is created according to the calibration parameters of the structured light system. And then the unwrapped phase of the object can be unwrapped pixel by pixel with reference to the minimum absolute phase map, by determining the number of fringe order. The proposed method has advantages of good robustness and low requirement for hardware, and it does not require any additional image acquisition and additional objects to obtain z0min, which can realize adaptive dynamic measurement. The experimental results show that under the same conditions, compared with the conventional temporal phase unwrapping method, the relative error of the proposed method is reduced by 14.33%, and the measurement method is simplified, which can effectively realize the three-dimensional shape measurement of objects..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 810001 (2019)
Improved Multi-exposure Image Pyramid Fusion Method
LIU Xin-long, and YI Hong-wei
Aiming at the partial overexposure and the loss of shadow detail in the multi-exposure Laplacian pyramid fusion algorithm, to replace the contrast function in the fusion coefficient of the original algorithm by using the phase congruency filter function was proposed. The algorithm can ignore the illumination and contraAiming at the partial overexposure and the loss of shadow detail in the multi-exposure Laplacian pyramid fusion algorithm, to replace the contrast function in the fusion coefficient of the original algorithm by using the phase congruency filter function was proposed. The algorithm can ignore the illumination and contrast when extracting the edge. The effect of the change on the image makes the fusion result more natural and richer in detail. The advantages of the algorithm were verified by multiple sets of sequence images, and compared with the original algorithm. The results show that in terms of subjective evaluation the fusion result of improved algorithm is natural, and it can better preserve the details of the dark part under the strong light background and reduce the halo at the light source. In terms of objective evaluation, the variance and histogram results of the high dynamic range image fused by the algorithm are obviously better than the original algorithm, and more information is retained than the original algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 810002 (2019)
A Polarizing Universal Multi-scale and Real-time Image Defogging Algorithm
L Xiao-ning, LIU Yang-yang, TAN Zheng, and L Qun-bo
In order to solve the problem that the existing polarization algorithms relied on the sky region to estimate the atmospheric parameters is interfered by white targets or highlighted regions, a universal multi-scale polarization dehazing method for image is proposed. The quadratic tree spatial index and image dark channIn order to solve the problem that the existing polarization algorithms relied on the sky region to estimate the atmospheric parameters is interfered by white targets or highlighted regions, a universal multi-scale polarization dehazing method for image is proposed. The quadratic tree spatial index and image dark channel prior method of polarization difference image are researched, which break through the limitations of the estimated model parameters depending on the sky to reconstruct the scene depth, and restore low-frequency foggless images with atmospheric scattering model. At the same time, the soft threshold denoising algorithm is studied to solve the residual noise problem in the target restoration process, combining with the transmission rate reconstructed by low-frequency information, the texture details are enriched by gradient enhancement. Finally, the clear image is reconstruct through wavelet. The experiment results show that the proposed algorithm effectively eliminates the limitation of estimating the atmospheric parameters subjected to the sky region, and suppresses the influence of noise with the operation efficiency improved greatly. The target in restored image is more clearly, and the details are more abundant..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 810003 (2019)
Astronomical Refraction Model Based on Real-time Parameters and Research of Radio Telescope Pointing Calibration Method
WU Yu-xiang, ZHANG Hong-bo, KONG De-qing, ZHU Xin-ying, ZHAO Rong-bing, and YU Lin-feng
Astronomical refraction in pointing error of large radio telescope was considered. An astronomical refraction model using real-time measured temperature, pressure and relative humidity was newly applied to pointing error calibration model. A simulation was used to compare traditional and real-time astronomical refractiAstronomical refraction in pointing error of large radio telescope was considered. An astronomical refraction model using real-time measured temperature, pressure and relative humidity was newly applied to pointing error calibration model. A simulation was used to compare traditional and real-time astronomical refraction model in different weather conditions. This calibration model was applied to pointing calibration of Shanghai Tianma 65 m Radio Telescope. The Ku-band experiment showed that the real-time astronomical refraction model is better than the traditional model. Pointing accuracy is 25.8% better under elevation of 20°, 45% better under elevation of 15° and 60% better under elevation of 10°. Pointing accuracy is 5.0″, which is 5.3% better than traditional model. The worsening of pointing accuracy at low elevation caused by astronomical refraction is basically removed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 811001 (2019)
Genetic Method to Optimize Dithering Technique in Phase Domain for High-quality Binary Fringe Generation
CAI Ning, CHEN Zhe-bo, LIN Bin, and CAO Xiang-qun
A genetic framework to optimize the dithering binary pattern in the phase domain was proposed, which searches a best binary patch instead of the whole pattern to handle the time-consuming difficulty of genetic algorithm. Experimental results show that the proposed technique can significantly improve the dithering fringA genetic framework to optimize the dithering binary pattern in the phase domain was proposed, which searches a best binary patch instead of the whole pattern to handle the time-consuming difficulty of genetic algorithm. Experimental results show that the proposed technique can significantly improve the dithering fringe quality and it is robust to different amounts of defocusing. The phase root mean square error reduces from 1.493, 1.209, 0.989 rad to 0.972, 0.749, 0.603 rad respectively, when the projector is mildly defocused, moderately defoucsed, and severely defocused..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 811002 (2019)
Analysis on the Effect of Tilt Compensation of Digital Zenith Camera
ZHOU Zhao-fa, XU Zhi-hao, LIU Xian-yi, and CHANG Zhen-jun
Aiming at the linear drift problem existing in the traditional tilt compensation process, the Ⅰ-Ⅱ observation position and the average value of the Ⅱ-Ⅰ observation position inclination correction were used for the inclination compensation. In order to reduce the influence of turntable rotation error on the tilt componeAiming at the linear drift problem existing in the traditional tilt compensation process, the Ⅰ-Ⅱ observation position and the average value of the Ⅱ-Ⅰ observation position inclination correction were used for the inclination compensation. In order to reduce the influence of turntable rotation error on the tilt component of zenith camera rotation axis, the effect of asymmetric rotation error on tilt compensation was deduced. The influence of astronomical coordinate errors of observation stations on the calibration of state parameters of inclinometer was analyzed, also. The results show that the latitude and longitude error can be increased from 0.337″,0.381″ to 0.265″,0.216″ by using the improved tilt compensation method, respectively. The asymmetry error of turntable can be controlled within 1′, so that the influence of the asymmetry error of turntable on the tilt compensation of the rotating axis of the camera can be controlled within 0.002″. When the astronomical coordinate error of the measuring station is equal to the positioning accuracy of the instrument itself, the influence of the astronomical coordinate error of the measuring station on the tilt compensation of the rotating axis is small, that is, the influence on the astronomical longitude is within 0.007″ and the influence on the astronomical latitude is within 0.008″. This study is helpful to the calibration of inclinometer parameters and the simultaneous determination of zenith camera location..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 812001 (2019)
Threshold-optimized Dithering Technique for High-quality 3D Shape Measurement
MENG Sen-sen, CAI Ning, and LIN Bin
In order to solve the problem that for defocus binary coding technique, the higher harmonic components in the fringe pattern cause measurement errors, a method of generating a binary image by threshold optimization dithering algorithm is proposed. By introducing the parameter γ to dynamically adjust the threshold, and In order to solve the problem that for defocus binary coding technique, the higher harmonic components in the fringe pattern cause measurement errors, a method of generating a binary image by threshold optimization dithering algorithm is proposed. By introducing the parameter γ to dynamically adjust the threshold, and considering the influence of different pixel gray values of the image on the dithering algorithm, the sinusoidality of the dithered image stripe after defocusing is improved. Simulation and experiments show that using the threshold optimization dithering algorithm, the fringe after defocusing has better sinusoidality when the parameter γ is 50. Compared with the traditional Floyd-Steinberg dithering algorithm, the root mean square error can be reduced by 0.013 7 rad when the fringe period is 40 pixel. The imaging is more clear for the sag of the model, and the image quality of the surface reduction of the object is significantly improved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 812002 (2019)
Internal Defect Detection of Material with Specular Using Double Imaging Mach-Zehnder System
ZHONG Shi-min, SUN Fang-yuan, CHEN Wei-jie, WU Shuang-le, and WANG Yong-hong
Considering the situation that the traditional shearography requires that the surface of the measured object must be sufficiently rough, thus it is hard to measure specular objects directly, an improved shearography system was proposed. The speckle generated by the laser passing through the frosted glass was reflected Considering the situation that the traditional shearography requires that the surface of the measured object must be sufficiently rough, thus it is hard to measure specular objects directly, an improved shearography system was proposed. The speckle generated by the laser passing through the frosted glass was reflected by the specular of the measured object to achieve the measurement. And we adopted double imaging Mach-Zehnder digital shearography to adjust the shear and carrier frequency independently and to expand the effective measurement region. In the defect detection experiments, the 8 k mirror panel was loaded by the thimble and the manufactured mirror material was loaded by heat loading. The experimental results revels that the distribution of defects detected by proposed method is basically consistent with that of manufactured defects and loading methods..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 812003 (2019)
Nonlinear Correction Method of Electrowetting Display Brightness Based on Human Visual System
LIN Shan-ling, LI Tian-tian, ZENG Su-yun, LIN Zhi-xian, GUO Tai-liang, and TANG Biao
Aiming at the influence of reflective electrowetting display on the definition and contrast of the content on the display under different ambient light, this paper proposes a brightness correction method based on preserving the difference of visual response of adjacent grayscale under different ambient light. The diffeAiming at the influence of reflective electrowetting display on the definition and contrast of the content on the display under different ambient light, this paper proposes a brightness correction method based on preserving the difference of visual response of adjacent grayscale under different ambient light. The difference is consistent with the response difference under reference ambient light. At the same time, in order to achieve precise modulation of the electrowetting display, the corrected brightness is subjected to secondary nonlinear correction. The method makes the relationship between the corrected voltage and the brightness curve more linear, improves the contrast of the electrowetting display, increases the image detail, and optimizes the display effect..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 812004 (2019)
Modulational Instability and Bright Discrete Solitons in Zigzag Optical Waveguide Array with Nonlinear Coupling
YAO Ying-bo, XIE Jia-yu, YIN Fen-fen, and TANG Bing
By the use of a linear stability analysis, the analytic expression for the growth rate of the disperse modulational instability in the zigzag optical waveguide array with nonlinear coupling is got, and the influence of the nonlinear coupling on the modulational instability region for different values of the next-nearesBy the use of a linear stability analysis, the analytic expression for the growth rate of the disperse modulational instability in the zigzag optical waveguide array with nonlinear coupling is got, and the influence of the nonlinear coupling on the modulational instability region for different values of the next-nearest-neighbor coupling coefficient is analyzed. The results indicate that varying the value of the nonlinear coupling parameter can evidently affect the shape of the modulational instability area. According to the result from the modulational instability analysis, the existence conditions of bright discrete solitons are predicted. Furthermore, analytical solutions for the bright discrete solitons in the present zigzag optical waveguide array are obtained by the multi-scale method. What is more, the existence conditions of such bright discrete solitons are discussed, which are manifested to be in agreement with the modulational instability analysis..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 819001 (2019)
Structural Design of Carbon Fiber-reinforced Plastics Barrel for Space Remote Sensing Camera
REN Guo-rui, LI Chuang, WANG Wei, XIE Yong-jie, XU Liang, WANG Yong-jie, and FAN Xue-wu
In this paper, a connecting barrel for space camera of Carbon Fiber-Reinforced Plastics (CFRP) is designed. Based on tolerance distribution in optics and composite lamination theory, the in-plane stiffness and thermal expansion coefficients due to lamination are analyzed, with structure optimized. Position error betweeIn this paper, a connecting barrel for space camera of Carbon Fiber-Reinforced Plastics (CFRP) is designed. Based on tolerance distribution in optics and composite lamination theory, the in-plane stiffness and thermal expansion coefficients due to lamination are analyzed, with structure optimized. Position error between primary and secondary mirrors, as well as modal distribution of the connecting barrel under gravity and temperature change are analyzed by finite element software. Finally, molding and fine tooling of the CFRP barrel is carried out, followed by optical inspection of the mirror system and appraisal mechanical test on the assembled camera. The analysis results show that the optical design and structural stability are satisfied by facts of 1) ＜0.002 mm eccentricity and ＜2″ tilt achieved on the secondary mirror under 1g gravity load and 2℃ temperature rise coupling; 2) 265 Hz fundamental frequency on the connecting barrel and on the secondary mirror combination system. Optical and mechanical performance tests show that the wavefront error of the primary and secondary mirror system meets the assembly requirements, and the barrel can bear the mechanical test of qualification level. The dual-terminal response of the barrel is amplified 1.7 times only, demonstrating desired damping property. The proposed barrel is merely 6.4 kg, which realizes light weight and high rigidity, thus satisfying the position accuracy and stability requirements on the primary and secondary mirrors for space cameras..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 822001 (2019)
Wavefront Aberration Beam Expansion-shrinkage Splicing Technology of Free-form Surface Lens
YU Jing, JIANG Wei-wei, and SHEN Xiao-yan
The measurement aperture is not matched when the wavefront sensor detects the free-form lens, and the measurement process and the data processing are cumbersome in the splicing detection method. To solve the problems above, a method is proposed for measuring the free-form surface lens. The wavefront aberration of a freThe measurement aperture is not matched when the wavefront sensor detects the free-form lens, and the measurement process and the data processing are cumbersome in the splicing detection method. To solve the problems above, a method is proposed for measuring the free-form surface lens. The wavefront aberration of a free-form surface lens is detected after expanding the diameter of a single measuring beam, and then the shrinked beam with the wavefront information of the beam expanding measurement region is received by the wavefront sensor. The sub-aperture wavefront aberrations of four diameters expanded by 10 times were obtained by designing the optical path measurement, and the wavefront reconstruction and splicing of the beam expansion sub-aperture were completed. In order to verify the reliability of the experiment, the measured beam aperture is reconstructed and compared with the subaperture peak and valley values generated by the Hartmann sensor, and the flatness of the beam aperture of the beam expander is observed. The experimental results show that the method can effectively increase the measurement range of the small-bore wavefront sensor and improve the detection efficiency. It can be used for the detection of wavefront aberration of large-diameter lenses..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 822002 (2019)
Development of a Bimorph Deformable Mirror Driven by Positive-voltage Actuators at Edge
PENG Tai-ran, LI Wen-lai, LOU Jun-qiang, CUI Yu-guo, and MA Jian-qiang
To improve the thermal stability of the deformable mirror, a bimorph deformable mirror driven by positive-voltage actuators at edge was proposed. The ring electrode of the deformable mirror was used to generate an overall defocus bias, while the discrete electrodes were used to correct the wavefront aberrations. The biTo improve the thermal stability of the deformable mirror, a bimorph deformable mirror driven by positive-voltage actuators at edge was proposed. The ring electrode of the deformable mirror was used to generate an overall defocus bias, while the discrete electrodes were used to correct the wavefront aberrations. The bidirectional deformation of the mirror can be realized by the positive voltage only, and the thermal deformation of the deformable mirror was low due to the symmetrical structure. The deformable mirror prototype was fabricated and tested. The test results show that the residual error of mirror surface after flattening is less than λ/30 (λ=1 064 nm). The typical low-order Zernike mode aberrations, such as astigmatism, defocus, trefoil and coma, are accurately reconstructed. The reconstructed amplitudes are 11.1 μm, 9.7 μm, 5.7 μm and 4.2 μm, with the normalized residual errors of 1%, 1%, 3.3%, and 6%, respectively. In addition, non-diffraction Airy beam is generated experimentally, which shows the excellent reconstruction performance of the deformable mirror..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 822003 (2019)
Tunable Optoelectronic Oscillator Based on Stimulated Brillouin Scattering and Coupled Dual-loop
FAN Feng, WANG Jia-bin, ZHU Wen-wu, HU Jing-jing, GU Yi-ying, WU Zhen-lin, HAN Xiu-you, and ZHAO Ming-shan
A tunable Optoelectronic Oscillator (OEO) based on stimulated Brillouin Scattering (SBS) and Coupled Dual-Loop (CDL) is proposed. The OEO combines SBS and CDL. The narrow bandwidth gain spectrum of SBS is employed to select the oscillation frequency and realize frequency tunability. By the join of CDL, the side mode ofA tunable Optoelectronic Oscillator (OEO) based on stimulated Brillouin Scattering (SBS) and Coupled Dual-Loop (CDL) is proposed. The OEO combines SBS and CDL. The narrow bandwidth gain spectrum of SBS is employed to select the oscillation frequency and realize frequency tunability. By the join of CDL, the side mode of the microwave signal is effectively suppressed, the phase noise of the microwave signal is decreased, the frequency and power stability of the microwave signal are improved. Experimental results show that microwave signals from 2 GHz to 18 GHz with the Side Mode Supression Ratio (SMSR) as high as 60 dB and the phase noise as low as -95 dBc/Hz at 10 kHz frequency offset are achieved. The frequency drift is less than 0.3 ppm and the power drift is lower than 0.2 dB at 10 GHz within 30 min in lab condition..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 823001 (2019)
4.1 μm High Power Mid-infrared Intra-cavity Optical Parametric Oscillator
WANG Yu-heng, LIU He-yan, WANG Ze-yu, LIU Hong-zhi, ZHENG Hao, YU Yong-ji, and JIN Guang-yong
A compact, acousto-optic Q-switched, high power 4.1 μm mid-infrared intra-cavity periodically poled lithium niobate crystal doped with magnesium oxide optically oscillating laser system was reported. Based on the dynamics model of the intra-cavity single resonant optical parametric oscillator, the overthreshold multiplA compact, acousto-optic Q-switched, high power 4.1 μm mid-infrared intra-cavity periodically poled lithium niobate crystal doped with magnesium oxide optically oscillating laser system was reported. Based on the dynamics model of the intra-cavity single resonant optical parametric oscillator, the overthreshold multiple of the intra-cavity optical parametric oscillator and the down-conversion efficiency of the optical parametric oscillator under high power was analyzed. The method of adjusting the threshold of optical parametric oscillation in the experiment was clarified and the down-conversion efficiency of optical parametric oscillation under high power was optimized. The introduction of in-band pumping and single-ended bonded crystal improved the thermal stability at high power pumping. Based on the optical field propagation theory and the resonant cavity stability theory, and considering the thermal effect of the gain medium, the three-wave fundamental mode pattern matching of fundamental frequency light, signal light and idle frequency light in the cavity was numerically simulated when the high-power pump was injected, in order to ensure the stable operation of the optical parametric oscillator at high power. The down-conversion efficiency of parametric laser was improved by adjusting the threshold of optical parametric oscillation. Finally, the output of mid-infrared high pulse repetition frequency watt-level laser at 4.125 μm was obtained, the laser repetition frequency were adjustable from 1 to 100 kHz, the pulse width was less than 9 ns, the maximum single-pulse energy was 36.7 μJ, the maximum peak power was 4.257 kW, the maximum output power was 1.12 W, the corresponding to down-conversion efficiency was 29.7%, and optical-optical conversion efficiency was 4.26%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 823002 (2019)
High-efficiency White Organic Light-emitting Diodes with Dual-emitting Layer
CHAI Yuan, WANG Jun-dong, LIU Si-yi, LIU Xuan, YUAN Xi, DONG He, and WANG Jin
The white organic light-emitting diodes with dual-emitting layer structure were prepared, using bipolar material 4,4'-bis(carbazol-9-yl)biphenyl (CBP) as host, blue fluorescent materials N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi) and orange phosphorescenThe white organic light-emitting diodes with dual-emitting layer structure were prepared, using bipolar material 4,4'-bis(carbazol-9-yl)biphenyl (CBP) as host, blue fluorescent materials N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi) and orange phosphorescent materials Iridium(III) bis(4-phenylthieno［3,2-c］pyridinato-N,C2')acetylacetonate (PO-01) as dopant. The device structure was optimized by adjusting the position of the emitting layer and inserting a spacer between the two emitting layers, then the photoelectric properties of the device were studied. The OLEDs were characterized by combining fluorescent and phosphorescent materials as the emitting layers, and using the same material CBP as both the host and spacer. The addition of the spacer improved the performance of the OLEDs. The maximum current and luminous efficacy of the OLEDs were 19.6 cd/A and 12.3 lm/W, respectively. The color coordinates varied from (0.438, 0.476) to (0.316, 0.389) when the brightness increased from 15 to 10 310 cd/m2, always in white zone..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 823003 (2019)
Strain-field-induced Energy Tuning for Self-assembled Quantum Dots-based Single-photon Sources Interfacing Atomic Transitions
LI Yang, TAO Lüe, GAN Fu-wan, and ZHANG Jia-xiang
In order to interface the self-assembled quantum dot light emitters and natural atoms towards quantum memory application, we designed and fabricated strain-field-induced energy-tunable single-photon sources by integrating quantum dots-containing nanimembrane onto a piezoelectric autcuator. A broad energy tuning range hIn order to interface the self-assembled quantum dot light emitters and natural atoms towards quantum memory application, we designed and fabricated strain-field-induced energy-tunable single-photon sources by integrating quantum dots-containing nanimembrane onto a piezoelectric autcuator. A broad energy tuning range has been achieved for both visible GaAs/AlGaAs quantum dots (9.1 meV) and near infrared InGaAs/GaAs quantum dots (4.2 meV). Meanwhile, with this strain tuning technique, the exciton emission energy of GaAs/AlGaAs quantum dots and InGaAs/GaAs quantum dots can be tuned to be in resonance with the D2 absorption lines of rubidium 87 (780 nm) and the 4I9/2→4F3/2 transition of neodymium ions in solid-state YVO4 (879.7 nm) respectively. This result provides a powerful tuning technique for realizing compact quantum memories based on semiconductor quantum dots and natural atom ensembles..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 8, 827001 (2019)
