Optimized Heralding Schemes for Single Photons

TL;DR

This paper proposes optimized spectral and temporal filtering techniques to enhance both the heralding efficiency and production rate of single-photon sources, overcoming a key trade-off in quantum photonics.

Contribution

It introduces a multimode theoretical framework and demonstrates that optimized filtering can universally improve heralded single-photon source performance regardless of spectral correlations.

Findings

Filters can be optimized for high efficiency and rate

Performance is consistent across different spectral correlations

Measurement scheme optimization surpasses source property tailoring

Abstract

A major obstacle to a practical, heralded source of single photons is the fundamental trade-off between high heralding efficiency and high production rate. To overcome this difficulty, we propose applying sequential spectral and temporal filtering on the signal photons before they are detected for heralding. Based on a multimode theory that takes into account the effect of simultaneous multiple photon-pair emission, we find that these filters can be optimized to yield both a high heralding efficiency and a high production rate. While the optimization conditions vary depending on the underlying photon-pair spectral correlations, all correlation profiles can lead to similarly high performance levels when optimized filters are employed. This suggests that a better strategy for improving the performance of heralded single-photon sources is to adopt an appropriate measurement scheme for the signal photons, rather than tailoring the properties of the photon-pair generation medium.