水平大气通道的光波前倾斜功率谱的测量及其频率分析  

Tilt Power Spectra Measurements and Frequency Analysis of Disturbed Wavefront in Horizontal Turbulence

作　　者：刘超[1,2] 胡立发[2] 穆全全[2] 曹召良[2] 宣丽[2] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,吉林长春130033 [2]中国科学院研究生院,北京100049

出　　处：《激光与光电子学进展》2011年第2期1-6,共6页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(60578035,50703039);吉林省与科学院科技合作项目(2008SYHZ0005)资助课题

摘　　要：在自适应光学系统设计和搭建过程中,一个关键的设计考虑因素就是倾斜镜的带宽,即Tyler频率。提出了一种根据实测的湍流整体倾斜功率谱直接计算Tyler频率的方法。首先利用Shack-Hartmann波前探测器,测量了水平湍流倾斜像差的功率谱,然后以一个衍射角为截止均方根残差,确定出Tyler频率。在实验所处的湍流条件下,水平湍流倾斜功率谱在高频部分与频率的-2次方成正比,与理论预言的-11/3次方成正比存在差异。还获得了Tyler频率的昼夜变化规律:在夜晚和清晨,水平湍流的Tyler频率变化缓慢,在实验所处的湍流条件下其值一般小于4Hz;在白天波动剧烈,实验测得其值最大可达到约20Hz。因此,对处于该湍流条件下的自适应光学系统,其倾斜镜的带宽需达到20Hz以上。In design of an adaptive optics system,a critical consideration is the bandwidth requirements for turbulence-induced tilt compensation,Tyler frequency.A method to evaluate the Tyler frequency is proposed according to the measured total tilt power spectrum.First,the power spectrum of the horizontal turbulence is measured through a Shark-Hartmann wavefront sensor.Then,the Tyler frequency is determined by which the tilt cut-off residual error of a diffraction angle is applied.The result illustrates that the tilt power spectrum is proportional to f-2 （f is temporal frequency） at high frequencies.At last,the circadian variation of Tyler frequency is acquired.It illustrates the important fact that,at night and early morning,the Tyler frequency of horizontal turbulence changes slowly,generally less than 4Hz in the turbulence condition,but it is volatile during the day,the largest up to about 20 Hz in Changchun.Therefore,the temporal bandwidth of the tip-tilt,in which the adaptive optics systems are used for the horizontal turbulence correction under such turbulence condition,must exceed 20 Hz.

关 键 词：大气光学 Tyler频率 倾斜功率谱 自适应光学 水平湍流 

分 类 号：O436[机械工程—光学工程]