Off-axis compressed holographic microscopy in low-light conditions

TL;DR

This paper demonstrates off-axis compressed holography for low-light imaging, using a single undersampled diffraction map and compressed sensing techniques to accurately recover holographic images with minimal measurements.

Contribution

It introduces a novel off-axis compressed holography method that combines single-exposure acquisition, compressed sensing, and spatial support constraints for low-light conditions.

Findings

Accurate holographic image recovery at 5 μs exposure

Reconstruction using only 9% of detector pixels

Effective imaging in low-light, high heterodyne gain regime

Abstract

This Letter reports a demonstration of off-axis compressed holography in low-light level imaging conditions. An acquisition protocol relying on a single exposure of a randomly undersampled diffraction map of the optical field, recorded in the high heterodyne gain regime, is proposed. The image acquisition scheme is based on compressed sensing, a theory establishing that near-exact recovery of an unknown sparse signal is possible from a small number of nonstructured measurements. Image reconstruction is further enhanced by introducing an off-axis spatial support constraint to the image estimation algorithm. We report accurate experimental recovering of holographic images of a resolution target in low-light conditions with a frame exposure of 5 \mu s, scaling down measurements to 9% of random pixels within the array detector.