Photon number discrimination without a photon counter and its application to reconstructing non-Gaussian states

TL;DR

This paper introduces a homodyne detection-based method for photon number resolution that can reconstruct non-Gaussian states without using a photon counter, enhancing quantum information processing capabilities.

Contribution

The authors develop and experimentally validate a technique for photon number discrimination using only homodyne detection, enabling non-Gaussian state reconstruction without photon counters.

Findings

Successfully demonstrated photon number resolution with homodyne detection

Reconstructed non-Gaussian states' statistics unambiguously

Method is highly efficient and compatible with telecom wavelengths

Abstract

The non-linearity of a conditional photon-counting measurement can be used to `de-Gaussify' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement; unambiguously reconstructing the statistics of the non-Gaussian one and two photon subtracted squeezed vacuum states. Although our photon number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon number resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum information tasks relying on the outcomes of mean values.