Measurement of stress vector based on polarization ptychography

Abstract

A novel stress vector measurement method combining ptychography and polarization technologies is proposed. By placing the stress sample in the probe-forming path and combining two circular polariscopes with a beamsplitter, the complex amplitudes of two orthogonal probe components are reconstructed under a single ptychographic scan. Three parameters are extracted with a simple and effective approach, where the isopachics and isoclinics are directly obtained from the phase information and the solution of isochromatics is easily realized by the combination of amplitude and phase. The feasibility of stress vector measurement is successfully verified through a classic diametrically compressed disc and a ring under diametric compression. This method avoids multiple scans, and has short data acquisition and reconstruction time and good adaptability for large samples. It can be further combined with single-shot ptychographical method to realize the dynamic measurement, which has great significance for online engineering applications.