基于精密光程差调制的时域干涉信号闭合相位检测方法研究

闭合相位法是实现长基线恒星光干涉高分辨成像的重要技术手段之一,获得精确的闭合相位信息是进行光干涉图像重构的先决条件.提出一种基于精密光程差调制的时域干涉信号闭合相位检测方法,在3路干涉臂上进行非冗余精密光程调制,并通过多次干涉测量结合数据拟合的方法消除光程差调制中存在的正弦误差,使得光程调制的精度达到20 nm以内.引入高速探测器件提升时域干涉信号的采样频率,对探测器上获得的时域干涉信号进行傅立叶变换处理,获得3路干涉臂精确的闭合相位信息.室内实验结果表明,基于精密光程调制的时域信号闭合相位计算精度可以达到1/50波长以内.

Research on Closure Phase Measurement Method of Temporal Domain Interferometric Signal Based on Precise Optical Path Difference Modulation

Closure phase method is one of the important techniques to realize high resolution imaging of long baseline stellar optical interferometry, and obtaining accurate closure phase information is a prerequisite for interferometric image reconstruction. A closure phase measurement method for the temporal domain interferometric signals based on the precise optical path difference modulation is proposed in this paper. The non-redundant precise optical path modulation is carried out on the three-way interferometer arm. With multiple interferometric measurements and data fitting, the sinusoidal error in optical path difference modulation is eliminated, and the optical path modulation accuracy is within 20nm. A high-speed detector is introduced to raise the sampling frequency of the temporal domain interferometric signal, and the temporal domain interferometric signal obtained on the detector is subjected to Fourier transform to obtain the accurate closure phase information of the three-way interferometer arm. The results of laboratory experiments show that the accuracy of the closure phase calculation of the temporal domain signal based on the precise optical path modulation can be improved up to 1/50 wavelength.