Multi-surface phase separation based on wavelength-tuning phase-shifting interferometry

Wavelength-tuning phase-shifting interferometry is a modern optical measurement method based on the propagation characteristics of light, which can deteunine sample topography by wavelength-level non-contact method with high-precision. The accuracy of this method can be up to nanometer and sub-nanometer precision. The measurement of transparent parallel plates is important and significant in optical measurement. Based on the design of window and sampling functions, the introduced 36 steps phase-shifting algorithm can effectively extract the target infounation. The influences of constant and first-order phase-shifting errors are analyzed. The least square separation method based on 19 steps iteration can deteunine the surface phase infounation accurately and separate surfaces including front, rear, thickness infounation, even the parasitic teen. The influence of different iteration steps for the PV and RMS values is considered, which provides the basis and reference for the design of the separation algorithm.