Rotational diffuser for speckle reduction in quantitative phase imaging

Abstract

A well-known speckle which comes from the coherent property of laser source has limited the laser imaging application. Quantitative Phase Imaging (QPI) also suffers from this speckle noise when illuminate with coherent source. A rotational diffuser is a considerable method to minimize the speckle by averaging the speckle contrast in time. Here, we employ the dual optical diffuser-static and moving diffusers — to suppress speckle noise in QPI. Continuous-wave laser is used to illuminate polystyrene micro-bead as a sample. Due to the averaging independent speckle pattern, speckle noise in phase image is reduced by maintaining the quality of fringe. The ability of moving diffuser in speckle noise suppression is presented in Fourier domain via Fast Fourier Transform (FFT) technique and topographic phase map. This work proposes a valuable technique for efficient suppression of the coherent speckle in QPI.