7 results on '"Jiaguo, Liu"'
Search Results
2. Laser beam shaping design based on micromirror array
- Author
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Wang Jing, Jiaguo Liu, Han Fang, Bida Su, and Xiaoli Fan
- Subjects
Physics ,Microlens ,business.industry ,Physics::Optics ,Compound eye ,Laser ,law.invention ,Lens (optics) ,Light intensity ,Optics ,law ,Physics::Accelerator Physics ,Focal length ,business ,Beam (structure) ,Gaussian beam - Abstract
In the practical application of the laser, it is necessary to use the laser beam shaping technology to shape the output beam of laser device to the uniform light intensity distribution. The shaping divergent optical system of compound eye integrator way is composed of beam expanding mirror group and lens array. Its working principle is to expand the output laser to a certain size of caliber, and then divide the beam with lens array into multiple sub beam, where the lens unit of lens array can control the divergence angle of sub beam through the design of focal length, with mutual superposition of the sub beam in far field, to make up for the nonuniformity of beam, so that the radiant exitance on the radiated surface may become uniform. In this paper, we use a reflective microlens array to realize the laser beam shaping. By through of the practical optical path model established, the ray tracing is carried out and the simulation results for single-mode Gaussian beam with noise circumstance is provided. The analysis results show that the laser beam shaping under different inputs can be effectively realized by use of microlens array. All the energy is within the signal window, with a high energy efficiency of more than 90%; The measured surface has a better uniformity, and the uniformity is better than 99.5% at 150m.
- Published
- 2017
3. Wavefront error correction with stochastic parallel gradient descent algorithm
- Author
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Xin Yu, Jiaguo Liu, Lei Zhao, Xinqi Hu, and Lin Li
- Subjects
Wavefront ,Nonlinear conjugate gradient method ,Stochastic gradient descent ,Computer science ,Error detection and correction ,Gradient descent ,Adaptive optics ,Gradient method ,Algorithm ,Backpropagation - Abstract
A novel type of adaptive optical system based on direct optimization of system performance metric is studied. The optimization method is based on stochastic parallel gradient descent (SPGD) algorithm. Theoretical analysis, computer simulations, and experimental results under point source and extended source conditions are presented.
- Published
- 2007
4. Optimal scanning function for capturing segmented mirror in space optics system
- Author
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Jiaguo Liu, Xia Wang, Kui Yang, Xin Yu, and Xiaofang Zhang
- Subjects
Segmented mirror ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,Deformable mirror ,Primary mirror ,Optics ,Position (vector) ,Computer Science::Computer Vision and Pattern Recognition ,Piston (optics) ,Computer vision ,Artificial intelligence ,business ,Adaptive optics ,Zemax ,Mathematics - Abstract
A great deal segmented mirror errors consisting of piston and tip-tilt exist when space large aperture segmented optics system deploys. These errors will result in the departure of segmented mirrors images from the view. For that, proper scanning function should be adopted to control actuators rotating the segmented mirror, so that the images of segmented mirror can be put into the view and placed in the ideal position. The key of capturing segmented mirror images is selecting an optimal scanning function. This paper put forward the optimal scanning function principle based on capturing images by the fastest velocity. The scanning functions, such as screw-type, rose-type, and helianthus-type and so on, have their own merits and demerits. In my paper, the scanning functions above will be analyzed and discussed. As a sample, a simulation experiment is carried to study the effects of different scanning functions on three mirror astigmatism system, whose primary mirror with six segmented mirror. In simulation experiment, the piston and tip-tilt errors scale and the ideal position of segmented mirror are given, three scanning functions above are used to realize the capture process by utilizing the improved optics design software ZEMAX, the relationship between scanning functions and optical system are analyzed and the optimal one is determined.
- Published
- 2007
5. Application of conformal optical design in star sensor
- Author
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Lin Li, Yifan Huang, Yan Li, and Jiaguo Liu
- Subjects
Physics ,business.industry ,Zernike polynomials ,Conformal map ,Field of view ,Star (graph theory) ,Deformable mirror ,symbols.namesake ,Optics ,symbols ,business ,Adaptive optics ,Zemax ,Optical aberration - Abstract
Star sensor is a special high accuracy photoelectric instrument. It is often used in navigation of aircraft, cruise missiles, and ballistic missiles, so the imaging quality of the optical system in a star senor is very important. The spherical windows with a small impact to imaging performance are usually used in traditional star sensors. However, the spherical surfaces are not ideal aerodynamic surfaces and would cause problems such as high drag. In this paper the conformal window whose outer shape is neither spherical nor flat is used in a star sensor. Unfortunately, the conformal shape introduces amounts of aberration which may lead to low imaging resolution. The various correctors can be used to eliminate the aberrations, for example, the fixed corrector, the arch, Zernike wedges, and the deformable mirror. The fixed corrector method is selected to decrease aberrations from the conformal window in this paper. The surface of the conformal window in the star senor is described as the Von Karman equation. The field of view is 17.6°×13.5°, and the size of the CCD pixel is 6.45 um×6.45um. The optical design program ZEMAX is used to design this system. After the optimization, under the max frequency of 77.52lp/mm, the MFT can almost achieve 30%. The design results show that the aerodynamic requirements can be satisfied by the application of the conformal window in the star sensor, and the aberrations can be corrected by proper ways.
- Published
- 2007
6. Polarization analysis in a very high resolution telescope (VHRT)
- Author
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Jiaguo Liu, Ying Zhang, Lin Li, and Yifan Huang
- Subjects
Physics ,Very high resolution ,Point spread function ,business.industry ,Strehl ratio ,Polarization (waves) ,law.invention ,Telescope ,Optics ,Software ,law ,Optical transfer function ,Radial polarization ,business - Abstract
A Very High Resolution Telescope (VHRT) is designed as a space-to-earth remote sensor and the polarization effect in this VHRT is analyzed in this paper. First, the theory of polarization effect is reviewed. Second, the Jones arithmetic of polarization aberrations in VHRT is presented. Then, CODE V software is used to realize the polarization ray trace in this system and the results of the polarization effect analysis are obtained. The output information includes the plot of Modulation Transfer Function (MTF), the plot of Point Spread Function (PSF), pupil map, relative illumination, illumination, distortion and Strehl ratio. Finally, effective methods to control the polarization effect in an optical system are given. According to the results of analysis, we have drawn the following conclusions. Polarization effect in an optical system shouldn't be ignored to improve the imaging quality; with the incident angle as small as possible to control the polarization effect. Coating design must be considered carefully for the optical design.
- Published
- 2006
7. Optical design of resource satellite system
- Author
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Yifan Huang, Jiaguo Liu, Lin Li, Yufeng Liu, and Yinhua Cao
- Subjects
Scanner ,business.industry ,Image quality ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Physics::Optics ,Satellite system ,Optical performance monitoring ,law.invention ,Optics ,Geography ,Relay ,law ,Hybrid system ,Electronic engineering ,Prism ,business ,Zemax - Abstract
The optical system of an infrared multi-spectrum scanner used on the resource satellite is presented in this paper. The principles of spectrum-dividing and imaging, the designing of optical system, the optimization of the assemblage and the adjusting of relay optical system are discussed. According to the general principles of infrared systems, R-C system is used in designing of the primary optical system. There are two methods to design the relay optical system, one of which consists of a complex prism and the other uses a binary optical element. The results and imaging quality of the two methods generated by ZEMAX are given. In the system using complex prism, each wavelength band consists of an R-C system. The diffractive system uses diffractive-refractive hybrid systems to divide spectrum, image and achromatize. The results show that the image quality of the designed system is good enough to meet the practical requirements.
- Published
- 2005
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