A polarization-based method for extracting phase from dual-frame interferograms

Interference measurement is a high-precision detection method for evaluating optical components and beam quality. Interferometry is commonly used for an optical element surface accurate test. But it is susceptible to interference from environmental and phase ambiguity issues. So a polarization-based method for extracting phase from dual-frame interferograms is proposed. We put forward a polarization-based method for extracting phase from dual-frame interferograms. This method only requires two interferograms with a phase difference of pi/2, which are processed using the extremum method and directly subjected to tangent and arctangent phase extraction to recover the surface shape. It enables simple and efficient extraction of the phase distribution of the tested optical element surface to be realized in a sub-millimeter scale dynamic range with a nanometer accuracy. The present invention does not require high-precision components such as phase shifters and spectrometers, and does not require preprocessing operations such as normalization and denoising of interferograms. It has the advantages of simple optical path, large measurement range, high accuracy, and high efficiency.