Imaging using quantum noise properties of light

TL;DR

This paper demonstrates a method to estimate object shapes by measuring quantum noise fluctuations in light, enabling imaging at low photon levels where traditional detection methods are ineffective.

Contribution

It introduces a noise-based imaging scheme utilizing quantum correlations in multi-spatial-mode vacuum-squeezed twin beams for shape estimation at low light intensities.

Findings

Quantum correlations enhance shape estimation sensitivity.

The method works in low-photon regimes where direct detection is challenging.

Homodyne detection of noise fluctuations enables imaging with minimal light exposure.

Abstract

We show that it is possible to estimate the shape of an object by measuring only the fluctuations of a probing field, allowing us to expose the object to a minimal light intensity. This scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough such that photon counting is not an option. We generate a few-photon state of multi-spatial-mode vacuum-squeezed twin beams using four-wave mixing and direct one of these twin fields through a binary intensity mask whose shape is to be imaged. Exploiting either the classical fluctuations in a single beam or quantum correlations between the twin beams, we demonstrate that under some conditions quantum correlations can provide an enhancement in sensitivity when estimating the shape of the object.