Xie Zhangning, Jin Tao, Lei Lihua, Lin Zichao, Xue Dongbai, Dun Xiong, Deng Xiao, Cheng Xinbin
Opt Express. 2024 May 6;32(10):16855-16866. doi: 10.1364/OE.517936.
The increasing line density of the reference grating and the accelerating miniaturization of ultra-precision displacement measurement technology necessitate more stable interferometric signal processing methods for high line density gratings, particularly in low signal-to-noise ratio scenarios. This paper presents a phase demodulation method for dynamic interferometric signals for high line density gratings. The Morlet wavelet transform is utilized to obtain the instantaneous frequency of the interferometric signal, integration of which yields the relative displacement, while adding adjacent relative displacements without gaps provides the absolute displacement during dynamic motion of the grating. In simulations with a signal-to-noise ratio ranging from 40 to 70 dB, the proposed method demonstrates greater robustness compared to the traditional method. By establishing a platform for repeated experiments and comparing it with traditional methods, it was found that the maximum deviation between calculation results obtained using this method and traditional methods is 0.8 nm, further confirming its potential application.
参考光栅线密度的不断增加以及超精密位移测量技术的加速小型化，使得针对高线密度光栅需要更稳定的干涉信号处理方法，特别是在低信噪比的情况下。本文提出了一种用于高线密度光栅动态干涉信号的相位解调方法。利用Morlet小波变换获得干涉信号的瞬时频率，对其进行积分得到相对位移，在动态运动过程中，将相邻无间隙的相对位移相加得到绝对位移。在信噪比范围为40至70 dB的模拟中，与传统方法相比，该方法表现出更强的鲁棒性。通过建立重复实验平台并与传统方法进行比较，发现使用该方法与传统方法获得的计算结果之间的最大偏差为0.8 nm，进一步证实了其潜在应用价值。
