S-transform application in phase extraction of spectrally resolved interferometry measuring step height.

Abstract

Spectrally resolved interferometry is widely used in the measurement of distance, displacement, film thickness, and surface morphology in micro/nano-scale geometric measurement. The core of spectrally resolved white-light interferometry is phase extraction. Temporal phase shifting, Fourier transform, wavelet transform, and other methods are commonly used in phase extraction of spectrally resolved interferometry. The S-transform, providing frequency-dependent resolution and having good time-frequency characteristics, is widely used in power quality disturbance analysis, seismic wave analysis, and phase recovery in profilometry. S-transform is used to extract the phase of the spectrally resolved white-light interferometry signal measuring step height. Compared with Fourier transform and wavelet transform, it is proved that S-transform is a feasible method in phase extraction of spectrally resolved interferometry measuring step height.