Experimentally accessing the optimal temporal mode of traveling quantum light states

TL;DR

This paper presents a practical, assumption-free method to determine the optimal temporal mode of traveling quantum light states directly from experimental data, enhancing quantum state characterization.

Contribution

It introduces a multimode analysis technique using eigenfunction expansion of autocorrelation functions to infer the temporal mode without prior assumptions.

Findings

Successfully applied to Fock states

Effective with Schrödinger cat-like states

Improves quantum state characterization

Abstract

The characterization or subsequent use of propagating optical quantum state requires the knowledge of its precise temporal mode. Defining this mode structure very often relies on a detailed a priori knowledge of the used resources, when available, and can additionally call for an involved theoretical modeling. In contrast, here we investigate a practical method enabling to infer the optimal temporal mode directly from experimental data acquired via homodyne detection, without any assumptions on the state. The approach is based on a multimode analysis using eigenfunction expansion of the autocorrelation function. This capability is illustrated by experimental data from Fock states and Schrodinger cat-like state preparation.