Programmable LED array reflectance microscopy for multi-contrast imaging

LED array microscopy is an emerging platform for computational imaging . Existing LED array systems often exploit transmission imaging geometries of standard brightfield microscopes that leave the rich backscattered field undetected. Here, we develop an LED array reflectance microscope capturing the sample’s backscattered signal. In particular, we demonstrate multimodal brightfield, darkfield, and differential phase contrast imaging on fixed and living biological specimens including Caenorhabditis elegans (C. elegans), zebrafish embryos, and live cell cultures. Video-rate multimodal imaging records real-time features of freely-moving C. elegans and the fast beating heart of zebrafish embryo. Our new reflectance mode is a valuable addition to the LED array microscopic toolbox.