Open AccessPhase imaging for absorptive phase objects using hybrid uniform and structured illumination Transport of Intensity Equation
Author(s) -
Yunhui Zhu,
Zhengyun Zhang,
George Barbastathis
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.028966
Subject(s) - poynting vector , optics , phase (matter) , intensity (physics) , physics , diffraction , phase retrieval , spatial frequency , signal (programming language) , light intensity , fourier transform , computer science , quantum mechanics , magnetic field , programming language
Transport of intensity equation (TIE) has been a popular and convenient phase imaging method that retrieves phase profile from the measurement of intensity differentials. Conventional 2-shot uniform illumination TIE can give reliable inversion of the phase from intensity in many situations of practical interest; however, it has a null space consisting of fields with non-zero circulation of the Poynting vector. Here, we propose the hybrid illumination TIE method to disambiguate such objects. By comparing the diffraction signals using uniform and structured (sinusoidal) illumination patterns, we obtain a modulation-induced signal that depends solely on the phase gradient. In this way, we also increase signal sensitivity in the low spatial frequency region.