Dynamic Focusing In Low-Coherence Quantitative Phase Imaging With Decoupling Of Spatio-Temporal Coherence Gating And Geometric Focusing

We describe an approach for arbitrarily adjusting the focal positions in quantitative phase imaging (QPI) based on a Linnik interferometer. Our setup employs a unique sample configuration in which transparent objects are imaged by a Linnik interferometer. By introducing a focus-tunable lens on top of the Linnik interferometer, we successfully decoupled the spatiotemporal coherence gating from the focal positioning and achieved dynamic focusing without disturbing the optical path length. Depth-sectioned quantitative phase images of polystyrene beads and live cultured cells were obtained without mechanical scanning. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement