DMD-based single-pixel off-axis interferometry for wavefront reconstruction of a biological sample

Single-pixel detecting is suitable for wavefront reconstruction in some special wavelengths where array detectors are immature or even unavailable and/or under low light conditions. However, most of the demonstrations are generally realized by multi-step phase-shifting interferometry with a liquid crystal spatial light modulator (LC-SLM) that has a slow modulation speed, which limits the reconstruction speed, thus restricting practical applications of the technique. Here, we propose to use a digital-micromirror-device-(DMD)-based single-pixel off-axis common-path interferometry (SOCI) for faster wavefront reconstruction. The method utilizes passive detection based on the DMD to realize SOCI for accelerating wavefront reconstruction. As compared to the LC-SLM-based phase-shifting techniques, since the modulation speed of the DMD is hundreds of times faster than that of the LC-SLM, the DMD-based SOCI accelerates several folds of reconstruction speed further, which, thus, makes the final wavefront reconstruction three orders of magnitude faster. The effectiveness and advantages of our method are experimentally demonstrated by quantitatively reconstructing the amplitude and phase images of a biological sample.