Obtaining a Single-Photon Weak Value from Experiments using a Strong (Many-Photon) Coherent State

TL;DR

This paper demonstrates a method to measure single-photon weak values using strong coherent states and simple click detectors, simplifying experimental requirements and overcoming the challenges of single-photon preparation.

Contribution

It introduces a novel approach to obtain single-photon weak values from experiments with many-photon coherent states, eliminating the need for heralded single-photon sources.

Findings

Weak values can be extracted from strong coherent states using click detectors.

The method involves subtracting no-click from click weak values and scaling by click probability.

Experimental feasibility is improved by avoiding slow single-photon sources.

Abstract

A common type of weak-value experiment prepares a single particle in one state, weakly measures the occupation number of another state, and post-selects on finding the particle in a third state (a 'click'). Most weak-value experiments have been done with photons, but the heralded preparation of a single photon is difficult and slow of rate. Here we show that the weak value mentioned above can be measured using strong (many-photon) coherent states, while still needing only a 'click' detector such as an avalanche photodiode. One simply subtracts the no-click weak value from the click weak-value, and scales the answer by a simple function of the click probability.