Simple setup to measure the phase map of transparent objects based on incoherent self-imaging

Abstract

We demonstrate how a simple optical setup based on the incoherent self-imaging phenomenon can be used to capture two-dimensional phase maps of transparent (phase) objects. We prove that the derivative of the object’s phase map can be extracted from the self-image. Simulations of self-images from a semi-spherical transparent object confirm the theoretical results. As proof-of-principle examples, experimental phase profiles obtained for water droplets on glass, and also a hydrophobic substrate are presented and compared. The phase maps are extracted from a single self-image, using the Fourier analysis, that makes this technique favorable for real-time measurements on dynamic samples.