Near single-photon imaging in the shortwave infrared using homodyne detection.

Wolley, O; Mekhail, S; Moreau, P-A; Gregory, T; Gibson, G; Leuchs, G; Padgett, M J · Proc Natl Acad Sci U S A · 2023

basic_science · Level V

Where this comes from

Abstract

Low-light imaging is challenging in regimes where low-noise detectors are not yet available. One such regime is the shortwave infrared where even the best multipixel detector arrays typically have a noise floor in excess of <b>100</b> photons per pixel per frame. We present a homodyne imaging system capable of recovering both intensity and phase images of an object from a single frame despite an illumination intensity of <b>≈</b>​<b>1</b> photon per pixel. We interfere this weak signal which is below the noise floor of the detector with a reference beam that is <b>∼</b>​<b>300</b><b>,</b> <b>000</b> times brighter, record the resulting interference pattern in the spatial domain on a detector array, and use Fourier techniques to extract the intensity and phase images. We believe our approach could vastly extend the range of applications for low-light imaging by accessing domains where low-noise cameras are not currently available and for which low-intensity illumination is required.