An Investigation of a Single Shot Dual Wavelength Polarised Interferometer which uses Carre and Four Step Phase Shift Algorithms

摘要

In this paper, we present a single-shot Dual-wavelength Polarized Interferometer (DPI) for measuring micro/nano-scale structured surfaces. This two-wavelength interferometer is combined with a polarization phase shift method to extend the 2π ambiguity range without any mechanical movement, enabling a single-shot approach to 'freeze' any unwanted environmental disturbances. Two fringe analysis algorithms, for the evaluation of surface topography, are presented. Three standard step height samples are measured in order to investigate the performance of the DPI. The system has the potential to be used for measuring moving surfaces, and the measuring range is limited by synthetic wavelength.