傅里叶望远镜大气湍流模拟实验

Laboratory Simulation of Atmosphere Turbulence for Fourier Telescopy

傅里叶望远术是一种能对深空暗弱目标进行高分辨率成像的技术.为了验证大气湍流对傅里叶望远镜系统的影响,进行了实验室环境下大气湍流模拟实验研究.在三束光傅里叶望远镜实验系统上,通过控制射频驱动器的输出功率来模拟光强抖动,改变射频驱动器的瞬时频率来模拟相位抖动.给出了实验理论依据,推导了湍流强度与实验变量的关系.实验在弱湍流闪烁和相位抖动两种情况下,分别给单束光和三束光加随机扰动并计算其Strehl比.结果表明,只在单束光上加扰动时重建图像影响不大;在三束光上加扰动时,弱湍流光强抖动对傅里叶望远镜系统的成像效果影响具有较大的随机性,而相位抖动会严重影响系统成像质量.因此,消除光强抖动和相位抖动影响是图像重建算法改进应该考虑的一个关键因素.

Fourier telescopy is a sort of high-resolution imaging technology for deep space object which is very small and dim. To verify the atmosphere turbulence net effect on Fourier telescope, the experimental demonstrations of atmosphere turbulence simulation were performed in a lab. Based on the iaboratory system of three-beam Fourier telescope, the scintillation and the phase jitter were simulated by changing the radio-frequency driver output power and the instantaneous frequency, respectively. The detail of the experimental principle was presented, and the relation between the turbulent intensity and experimental variable was built. For different cases with random scintillation and phase jitter in weak turbulence, the experiments were conducted for single beam and three beams, and all the results＇ Strehl ratio were calculated. The experimental results indicate that, with single beam holding turbulence, there are no obvious change for all the reconstructed image; with three beams adding turbulence, the image quality of the Fourier telescope system is few influenced by weak scintillation, but is severe affected by phase jitter. As indicated, removing the phase and light intensity jitter effect is a key point of improving the image reconstruction arithmetic.