Infrared photon-number-resolving imager using a Skipper-CCD

TL;DR

This paper presents an infrared photon-number-resolving imager using a Skipper-CCD that significantly reduces readout noise, enabling high-resolution, low-light imaging crucial for quantum metrology and astronomy.

Contribution

The development of a Skipper-CCD based infrared imager with ultra-low noise and photon-number resolution across a wide dynamic range is a novel advancement.

Findings

Readout noise reduced to less than 0.2 electrons per pixel

Able to distinguish shapes with less than two photons per pixel

Demonstrates potential for high-precision infrared imaging in scientific applications

Abstract

Imaging in a broad light-intensity regime with a high signal-to-noise ratio is a key capability in fields as diverse as Quantum Metrology and Astronomy. Achieving high signal-to-noise ratios in quantum imaging leads to surpassing the classical limit in parameter estimation. In astronomical detection, the search for habitable exoplanets demands imaging in the infrared its atmospheres looking for biosignatures. These optical applications are hampered by detection noise, which critically limits their potential, and thus demands photon-number and spatial resolution detectors. Here we report an imaging device in the infrared wavelength range able to arbitrarily reduce the readout noise. We built a Measured Exposure Skipper-CCD Sensor Instrument equipped with a thick back-illuminated sensor, with photon-number-resolving capability in a wide dynamic range, spatial resolution, high quantum efficiency in the near-infrared and ultra-low dark counts. This device allows us to image objects in a broad range of intensities within the same frame and, by reducing the readout noise to less than 0.2e$^-$, to distinguish even those shapes with less than two photons per pixel, unveiling what was previously hidden in the noise. These results pave the way for building high-standard infrared imagers based on Skipper-CCDs.