Improving the purity of heralded single-photon sources through spontaneous parametric down-conversion process*

The high-purity single-photon source plays an important role in the field of quantum information. Usually, it is generated through spontaneous parametric down-conversion process. In this paper, we investigate and summarize a few approaches on obtaining single-photon sources with a high purity using either PPKTP or PPLN nonlinear crystals. Moreover, we present improved schemes to increase the purity based on existing work, corresponding applicable conditions and procedures are discussed and analyzed. Besides, we carry out numerical simulations and show that nearly perfect purity can be reached even without using any filters. Therefore, this work might provide valuable references for the generation and application of high purity single-photon sources.

Automated summary

This paper investigates several methods to obtain high-purity single-photon sources using PPKTP or PPLN nonlinear crystals, presents improved schemes for purity enhancement, conducts numerical simulations demonstrating near-perfect purity can be achieved without filters. This work may offer valuable references for the generation and application of high-purity single-photon sources.