Journals >Opto-Electronic Engineering
Contents
2018
Volume: 45 Issue 11
11 Article(s)
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Research Articles
Automatic exposure technology for space camera
Xie Jing, Hu Yongfu, Tang Qi, and Zhang Yuanye
Highly integrated miniature cameras based on CMOS sensors have been used more and more widely in spacecraft. Space camera can accomplish the key operation record, remote sensing and near celestial observation of spacecraft, and has the characteristics of small volume, light weight and intelligent. In order to achieve aHighly integrated miniature cameras based on CMOS sensors have been used more and more widely in spacecraft. Space camera can accomplish the key operation record, remote sensing and near celestial observation of spacecraft, and has the characteristics of small volume, light weight and intelligent. In order to achieve a good imaging effect, automatic exposure technology which is suitable for the space environment is indispensable. In this paper, a fast adaptive exposure algorithm is proposed for the particularity of space environment and the irreversibility of spatial tasks. The algorithm is based on energy analysis, weighting statistics on the target according to the statistics of the image, and using the lookup table method to calculate the optimal exposure time. The double objective adjustment range is set, so that the automatic exposure algorithm converges better. The experimental results show that the algorithm can obtain the best exposure time quickly and stably. The speed of exposure is fast and the stability is high. It is very suitable for space scene detection. The correlation algorithm has been successfully applied to multiple on orbit models..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180033 (2018)
Polarization calibration unit design of 1.8 m Chinese large solar telescope
Yao Benxi, Rao Changhui, and Gu Naiting
It is the main task for the Chinese large solar telescope (CLST) with a 1.8 m aperture to measure the solar polarization with a high accuracy and sensitivity. However, the telescope system itself will introduce instrumental polarization. It also will change constantly with the rotating of the telescope and will reduce It is the main task for the Chinese large solar telescope (CLST) with a 1.8 m aperture to measure the solar polarization with a high accuracy and sensitivity. However, the telescope system itself will introduce instrumental polarization. It also will change constantly with the rotating of the telescope and will reduce the accuracy. Therefore, a calibration unit is necessary to calibrate it. In this paper, we introduced the polarization calibration method and proposed a calibration unit structure..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180058 (2018)
Radially polarized Bessel lens based on all-dielectric metasurface
Chen Junyan, Zhang Fei, Zhang Ming, Cai Jixiang, Ou Yi, and Yu Honglin
In this paper, a radially polarized Bessel lens based on a dielectric metasurface is proposed. It can efficiently convert linearly polarized light into radially polarized light and simultaneously achieve non-diffracting Bessel beams. Under the incidence of linearly polarized light, the left and right handed components In this paper, a radially polarized Bessel lens based on a dielectric metasurface is proposed. It can efficiently convert linearly polarized light into radially polarized light and simultaneously achieve non-diffracting Bessel beams. Under the incidence of linearly polarized light, the left and right handed components of linearly polarized light are independently regulated by the asymmetric photon spin-orbit interaction. Finally, polarization conversion and wavefront control are simultaneously achieved by spin recombination. At wavelength of 532 nm, the numerical aperture NA=0.9, and the metalenses achieve a focus focal spot beyond the diffraction limit. The study has potential applications in particle acceleration and super-resolution imaging..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180124 (2018)
Design and implementation of high sensitivity micro spectrometer based on area array CCD
Xu Danyang, and Du Chunnian
The area array CCD has the advantages of high sensitivity and wide dynamic range, which is suitable for fluorescence measurement, DNA sequencing, Raman spectroscopy and low photometric detection. Therefore, it is of great practical value to develop high sensitivity micro fiber spectrometer based on area array CCD. The The area array CCD has the advantages of high sensitivity and wide dynamic range, which is suitable for fluorescence measurement, DNA sequencing, Raman spectroscopy and low photometric detection. Therefore, it is of great practical value to develop high sensitivity micro fiber spectrometer based on area array CCD. The optical resolution of 1 nm is obtained by using an optimized cross-asymmetric Czerny-Turner optical system structure. By combining the design methods of DC-DC and LDO, the complex power system with 6 voltage outputs is realized through USB power supply. The CCD drive timing design is achieved by Verilog HDL language and the signals are output through Altera's EPM7064 chip. After the CCD output video signal is converted by high-speed 16 bit AD chip AD9826, digital signals are stored in a separate static RAM, allowing dacquisition and reading of data to be separated. The sensitivity of designed micro-high sensitivity spectrometer is 11 times of that of spectrometer based on linear array CCD. Furthermore, it has a dynamic range of 20000: 1 and a signal-to-noise ratio of 500: 1. This work greatly improves the microfiber spectrometer performance..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180152 (2018)
Theoretical investigation of surface plasmonic polariton-based electro-optical modulator with low polarization dependence
Jin Lin, Song Shichao, Wen Long, and Sun Yunfei
Plasmonic modulators essentially support only transverse magnetic mode. A plasmonic modulator consisting of hybrid plasmonic waveguides in both vertical and horizontal directions is proposed to reduce the polarization- dependence. In a combined waveguide, surface plasmon polariton (SPP) modes polarized in the vertical Plasmonic modulators essentially support only transverse magnetic mode. A plasmonic modulator consisting of hybrid plasmonic waveguides in both vertical and horizontal directions is proposed to reduce the polarization- dependence. In a combined waveguide, surface plasmon polariton (SPP) modes polarized in the vertical and horizontal directions exist in the correspondingly oriented hybrid plasmonic waveguide. The light modulation is investigated by tuning the carrier density of the accumulated layer where occurs at the dielectric-ITO interfaces. In an optimized structure, a ΔIER (a difference between the extinction ratios of two polarization modes) under 0.01 dB/μm is demonstrated at ITO “ENZ”-state by simulation. The energy flux clearly shows the polarization-selective coupling between the polarized guided modes in the feeding silicon waveguide and those in the combined waveguide. Coupling efficiency above 74% is obtained for both polarizations. The proposed plasmonic combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180156 (2018)
Control of EOT of subwavelength metal bullseye structures by coaxial nano-columns
Yang Zehua, Song Yang, Chen Shuang, and Gao Yachen
The bullseye structure is a classic nano-optical structure. This article designs a new bullseye structure with coaxial nano-pillars. We used the time-domain finite difference method (FDTD) to study the EOT of the structure. Studies show that the radius and height of the column have a significant impact on the transmissThe bullseye structure is a classic nano-optical structure. This article designs a new bullseye structure with coaxial nano-pillars. We used the time-domain finite difference method (FDTD) to study the EOT of the structure. Studies show that the radius and height of the column have a significant impact on the transmission characteristics. The proper choice of the radius and height of the column will support the maximum transmission intensity. In addition, the bullseye structure has a higher sensitivity to the environmental refractive index. Theoretical analyses show that the enhancement transmission effect of the structure is caused by the interaction between the local surface plasmon and the surface plasmon polarization. This provides a new idea for the development and application of nano- photonic components..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180207 (2018)
Double optical wedge optical axis pointing adjustment technology
Gao Fei, and Wang Miao
Because the double-wedge system can accurately adjust the orientation of the optical axis, it has the advantages of simple and compact structure, fast adjustment speed, and large adjustment angle. In order to meet the needs of a certain product, optical axis adjustment trajectories of concentric circles and zigzags areBecause the double-wedge system can accurately adjust the orientation of the optical axis, it has the advantages of simple and compact structure, fast adjustment speed, and large adjustment angle. In order to meet the needs of a certain product, optical axis adjustment trajectories of concentric circles and zigzags are realized. Based on the existing theories, this paper establishes the corresponding formula by establishing the relationship between the optical axis deflection angle and the bi-wedge rotation angle model, and combines the Matlab simulation, the fitting and the actual product testing, and designs the use of ARM and computer-controlled bi-optical wedges to adjust the orientation of the optical axis. The results show that the error of the optical axis pointing adjustment of the scheme is less than 0.5°, and the expected trajectory can be achieved to meet the requirements of actual products..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180218 (2018)
Optical characteristics of one dimensional metal-dielectric photonic band gap material
Zhao Yali, Li Xufeng, Jia Kun, Ma Jiangjiang, Li Qiaoyan, and Wei Xuehong
This paper describes the optical transmittance and reflection of one dimensional metal-dielectric photonic- band gap material (1D M-D PBG), which is made of different thicknesses ITO and Ag layers. It is found that structures with a unit size below 80 nm and a smaller metal fraction leads to improvement of optical tranThis paper describes the optical transmittance and reflection of one dimensional metal-dielectric photonic- band gap material (1D M-D PBG), which is made of different thicknesses ITO and Ag layers. It is found that structures with a unit size below 80 nm and a smaller metal fraction leads to improvement of optical transmittance. For unit sizes larger than 80 nm, the reflection at the shorter and longer wavelengths increases. This is due to the generation of a structural and plasmonic band gap. In addition, the reflection in both ranges increases and broadens by increasing Ag films thicknesses. The reflection spectrum induced by structure shifts towards longer wavelength as a result of unit size increasing and the reflection due to plasmonic band gap piles beyond to optical range. The results are very useful for optical filter of 1D M-D PBG design..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180239 (2018)
Visual odometry with three-stage local binocular BA
Zhao Tong, Liu Jieyu, and Li Zhuo
In this paper, a three-stage local binocular BA (bundule adjustment) is proposed based on the ORB-SLAM2 algorithm, which is based on the large value of the initial value and the binocular camera model. In order to reduce the influence of cumulative error on 3D-2D matching in the uniform model, the ring matching mechaniIn this paper, a three-stage local binocular BA (bundule adjustment) is proposed based on the ORB-SLAM2 algorithm, which is based on the large value of the initial value and the binocular camera model. In order to reduce the influence of cumulative error on 3D-2D matching in the uniform model, the ring matching mechanism is introduced to eliminate the mismatched again and match the key frame map point with the current frame 3D-2D projection. In the tracking part of the local map optimization phase, the normal frame between the two nearest key frames is also optimized as the local frame when the key phase is inserted into the key frame. KITTI data set experiments show that the three-stage local binocular beam method has more accurate 3D-2D matching compared with ORB-SLAM2, which improves the optimization constraint and improves the motion estimation and optimization precision..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180244 (2018)
High Q-factor terahertz metamaterial based on analog of electromagnetically induced transparency and its sensing characteristics
Ma Changwei, Ma Wenying, Tan Yi, and Tang Yuzhu
A high Q-factor terahertz metamaterial with analog of electromagnetically induced transparency (EIT) effect is designed. The structural unit is composed of double metal wires parallel to each other and a vertical single metal wire in the middle. The single wire, double wires and composite structures are simulated respeA high Q-factor terahertz metamaterial with analog of electromagnetically induced transparency (EIT) effect is designed. The structural unit is composed of double metal wires parallel to each other and a vertical single metal wire in the middle. The single wire, double wires and composite structures are simulated respectively, and the influence of the position and size of the metal wires on the transmittance and quality factor Q of the composite structure is analyzed. The results show that the EIT-like effect occurs with the horizontal shift of the single metal wire and the transmittance and the Q-factor are changed with the increase of the offset distance. Moreover, different Q-factor can be achieved by adjusting the structure and size. By optimization, when the offset distance is 8 μm, a transparent window with 3 dB bandwidth of approximate 11.56 GHz is obtained near 0.73 THz. The corresponding Q-factor is 63.09 and the transmittance is 0.50. Finally, the sensing characteristics of the resonator is measured, showing excellent sensing performance. The refractive index sensitivity is 60.69 GHz/RIU, and FOM value is 5.25/RIU..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 11, 180298 (2018)
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