共查询到17条相似文献,搜索用时 125 毫秒
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为克服大气非等晕的影响,多层共轭自适应光学(MCAO)系统被广泛应用于太阳望远镜,以有效扩大校正视场。仅考虑由于大气非等晕造成的系统理论误差,研究了变形镜(DM)个数及其共轭高度对太阳多层共轭自适应光学(MCAO)系统性能的影响。结果表明,MCAO系统中DM的最佳共轭高度取决于大气湍流的分布;理论上,太阳望远镜(D/r0=28.57)视场为1arcmin时,只需两块DM,太阳MCAO系统斯特列尔比(SR)可达0.55,基本满足太阳望远镜的观测要求;同时,随着太阳望远镜口径的增大,需通过增加DM个数以满足其在大视场观测的需求。 相似文献
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激光导引星大气湍流波前非等晕性误差的像差模式分解 总被引:2,自引:1,他引:1
激光导引星概念解决了自适应光学技术的信标问题,同时带来了无法克服的非等晕性误差。将高度聚焦非等晕性误差和角度等晕性误差统一起来考虑,分析激光导引星的大气湍流波前各阶模式的非等晕性误差,并给出了解析模型。同时分析了瑞利导星和纳导星的大气湍流波前的模式非等晕性相对误差,在没有角度偏离的情况下,90km的钠导星的模式非等晕性误差明显小于15km的瑞利导星,但是它对角度的敏感程度却远远大于端利导星。采用激光导引星的自适应光学系统用于大气湍流的校正,选择较低阶的模式校正就可以达到较好的效果,而且即使目标与导引星的偏角大于等晕角,选择低阶模式也可以达到有效的部分校正效果。 相似文献
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自泵浦位相共轭反射的实验研究 总被引:1,自引:1,他引:0
本文通过检测BaTiO_3晶体的二波耦合增益系数P和自泵浦位相共轭反射率R对随入射角的变化关系,经过理论分析指出R的角度依赖性是P的角密依赖性的结果;详细地解释了全内反射自泵浦位相共轭的双区域耦合理论,指出位相共轭输出的频移特性是泵浦光在双区域间“振荡”的结果;并解释了自泵浦形成的阈值特性。 相似文献
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理论分析和讨论了基于频域相位共轭技术的交叉相位调制所致信号失真的复原和补偿机理,数值模拟了在交叉相位调制作用下,高斯脉冲在中距相位共轭光纤系统中的传输演化过程.结果表明,频域相位共轭技术能够抑制交叉相位调制对光纤系统中传输信号的损害,复原其所导致的信号失真,并能够同步补偿群速度色散和自相位调制非线性效应所导致的信号失真.合适的初始脉冲时延和初始脉冲啁啾有利于频域相位共轭技术对交叉相位调制所致信号失真的抑制.
关键词:
频域相位共轭
交叉相位调制
色散
自相位调制 相似文献
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A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
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Mohammad Moradi 《Optical Review》2008,15(2):125-129
The goal of this study was to analyse anisoplanatism of adaptive optics under an inhomogeneous turbulent atmosphere over a
pupil of finite size. By means of a numerical model with layers of turbulence software was proposed by which point spread
function (PSF), optical transfer function (OTF) as well as system isoplanatic angle can be calculated. Atmospheric turbulence
was simulated with the aid of a set of moving random phase screens with arbitrary statistics. Both reference and target are
assumed to be the point light sources. To simulate atmospheric turbulence we applied the concept of a number of moving random
phase screens with Kolmogorov spectrum. In my investigation I used the model of the Shack-Hartmann wave front sensor and the
ideal model of a wave front adaptive mirror that is assumed to reproduce a given number of Zernike polynomials without time
delays. The designed software allows calculation of instantaneous and average values of phase correction errors at different
angles between a reference beacon and target source. Simulations can be made with a broad range of parameters of an adaptive
system and atmospheric turbulence. The system of the model allows changing of the control algorithm of phase correction. Both
common phase conjugation and weighted phase conjugation algorithm have been tested. This program is capable of calculating
the effects of beam diffraction during propagation in the atmosphere. 相似文献
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非线性热晕效应自适应光学位相补偿 总被引:3,自引:1,他引:2
采用已建立的一套较完整的包括真实自适应光学位相补偿系统仿真的高能激光大气传输的数值模拟程序,对非线性热晕应相偿进行了计算。分析了非线性热晕效应位相补偿不稳定性的基本特征。 相似文献
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Huiyun Wu Shen Sheng Zhisong Huang Siqing Zhao Hua Wang Xiegu Xu Zhenhai Sun Rui Xiao 《Optical and Quantum Electronics》2013,45(5):411-421
Beam propagation through a double-adaptive-optics optical system in turbulent atmosphere has been investigated. A typical model of optical systems with the double-adaptive-optics configuration is established, principles of the two adaptive optics and theory of beam propagation through the optical system in turbulent atmosphere are analyzed. Power efficiency and beam quality (BPF) of the received beam are introduced to evaluate performance of the optical system. Under the H-V 5/7 turbulent model, influences of the two adaptive optics installations are numerically calculated, respectively. Results show that the adaptive optics at the launcher can improve both power efficiency and beam quality of the received beam, the adaptive optics at the receiver can significantly improve beam quality of the received beam. Evolution of the system performance with the increase of adaptive optics correction order is numerically simulated, and results show that the double-adaptive-optics configuration has great advantages in improving beam quality of the received beam in optical systems with beam long-distance propagation through the turbulent atmosphere. 相似文献
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Flicker RC 《Optics letters》2001,26(22):1743-1745
The way in which the sequence of phase correction impinges on performance in multiconjugate adaptive optics systems is described. When multiple phase modulators with different conjugate ranges are used, the conjugate images of the phase modulators in the atmosphere must be reimaged in the reverse order post focus, and adaptive phase correction applied in this sequence for perfect amplitude and phase cancellation. Performing the correction without relay optics results in residual amplitude and phase aberrations. It is shown, by Monte Carlo simulations of Fresnel propagation, that the effects of wave optical propagation become nonnegligible at visible wavelengths and for large air masses. 相似文献
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C.P. Wang 《Optics Communications》1975,14(2):200-204
For optical imaging through turbulence, a measure which specifies how close a given imaging system is to be isoplanatic is defined. Its defendence on the spatial resolution, seeing angle, and turbulence structure is given. The result shows that for low resolution imaging, the isoplanatic condition is usually satisfied, while for diffraction-limited imaging, the isoplanatic condition does restrict the seeing angle to be small. 相似文献