Ptychographic Mueller matrix imaging (PMMI): principle and proof-of-concept demonstration.

Quantitative characterization of optical anisotropies is extremely important for wide fields and applications. The Mueller matrix, providing all the polarization-related properties of a medium, is a powerful tool for the comprehensive evaluation of optical anisotropies. Here, we propose a ptychographic Mueller matrix imaging (PMMI) technique, which features the Mueller matrix polarization modulation being introduced into the ptychography. The ptychographic reconstruction is performed for each polarization state, and the Mueller matrix can be determined from the reconstructed polarization-modulated amplitude images. A proof-of-concept of the proposed PMMI is implemented, and both simulations and experiments are conducted to demonstrate the validity of the method. Results indicate that the imaging resolution of the home-built PMMI apparatus achieves 1.550 µm at the wavelength of 633 nm, which is of the highest level for the Mueller matrix imaging to the best of our knowledge. A customized birefringent specimen is characterized, and both retardance and axis azimuth are quantitatively evaluated.