Single-shot isotropic quantitative phase microscopy based on color-multiplexed differential phase contrast

Abstract

We present a single-shot isotropic quantitative phase imaging method based on color-multiplexed differential phase contrast. In our method, the illumination source is modulated by an LCD into an annular color-multiplexed pattern matching the numerical aperture of the objective precisely to maximize the frequency response for both low and high frequencies (from 0 to 2NAobjλ). In addition, we propose an alternating illumination scheme to provide a perfectly circularly symmetrical phase transfer function, achieving isotropic imaging resolution and signal-to-noise ratio. A color camera records the light transmitted through the specimen, and three monochromatic intensity images at each color channel are then separated and utilized to recover the phase of the specimen. We display the derivation, implementation, simulation and experimental results, which demonstrate that our method accomplishes high resolution, noise-robustness and reconstruction accuracy phase reconstruction at camera-limited frame rates.