Validating the calibrated creation of heralded single photons

TL;DR

This paper demonstrates a practical method for accurately characterizing heralded single photons generated via parametric down-conversion in a waveguide, using simple photon-correlation measurements to determine key quantum state properties.

Contribution

It introduces an extended, loss-tolerant toolbox for characterizing heralded single photons, combining conventional figures-of-merit for improved accuracy in state assessment.

Findings

Accurate determination of mean photon number and photon-number parity from simple measurements.

Implementation of a heralded single photon source in telecom wavelength range.

Enhanced methods for calibrated creation and analysis of heralded single photons.

Abstract

Coincidence-count discrimination have turned utterly practical in the characterization of photon-pair processes and heralded single photons. Here, we implement a heralded single photon source based on parametric down-conversion (PDC) in a PP-KTP waveguide in the telecom wavelength range involving a low number of optical modes. We extend the toolbox for the loss-tolerant state characterization by combining conventional figures-of-merit in order to access the heralded state's mean photon number and its photon-number parity. Our experiment demonstrates that an accurate determination of these characteristics is possible just through simple photon-correlation measurements. We believe that our results can find usage in the calibrated creation of heralded single photons and in determining the expectation values of observables that are crucial for denoting a single quantum.