Zhang M J, Jing N, Li K W, Wang Z B
School of Information and Communication Engineering, North University of China, Taiyuan 030051, China.
Engineering and Technology Research Center of Shanxi Provincial for Optical-Electric Information and Instrument, North University of China, Taiyuan 030051, China.
Rev Sci Instrum. 2018 Jan;89(1):013105. doi: 10.1063/1.5020714.
A drifting model for the resonant frequency and retardation amplitude of a photo-elastic modulator (PEM) in the photo-elastic modulated Fourier transform spectrometer (PEM-FTs) is presented. A multi-parameter broadband-matching driving control method is proposed to improve the thermal stability of the PEM interferometer. The automatically frequency-modulated technology of the driving signal based on digital phase-locked technology is used to track the PEM's changing resonant frequency. Simultaneously the maximum optical-path-difference of a laser's interferogram is measured to adjust the amplitude of the PEM's driving signal so that the spectral resolution is stable. In the experiment, the multi-parameter broadband-matching control method is applied to the driving control system of the PEM-FTs. Control of resonant frequency and retardation amplitude stabilizes the maximum optical-path-difference to approximately 236 μm and results in a spectral resolution of 42 cm. This corresponds to a relative error smaller than 2.16% (4.28 standard deviation). The experiment shows that the method can effectively stabilize the spectral resolution of the PEM-FTs.
提出了一种用于光弹性调制傅里叶变换光谱仪（PEM-FTs）中光弹性调制器（PEM）共振频率和延迟幅度的漂移模型。提出了一种多参数宽带匹配驱动控制方法，以提高PEM干涉仪的热稳定性。基于数字锁相技术的驱动信号自动调频技术用于跟踪PEM变化的共振频率。同时，测量激光干涉图的最大光程差，以调整PEM驱动信号的幅度，从而使光谱分辨率稳定。在实验中，将多参数宽带匹配控制方法应用于PEM-FTs的驱动控制系统。共振频率和延迟幅度的控制将最大光程差稳定在约236μm，光谱分辨率为42cm。这对应于小于2.16%（4.28标准差）的相对误差。实验表明，该方法能有效稳定PEM-FTs的光谱分辨率。
