Spontaneous parametric down-conversion (SPDC) in a laser pumped optical nonlinear medium can produce heralded single photons with a high purity but a very low yield. Improving the yield by increasing the pump power in SPDC inevitably reduces the purity due to excitation of multi-photon events. We propose a scheme to overcome this purity-yield trade-off by suppressing multi-photon events in a cavity-enhanced SPDC via the photon blockade effect. By introducing a strong photon-photon interaction into the intracavity medium and increasing the pump power, we can improve the available single-photon yield to larger than 90%, while maintaining a high purity of 99%, towards on-demand generation of single photons through the SPDC process. Our quasi-on-demand SPDC sources may boost single-photon-based quantum information technology.
@article{arxiv.2104.04178,
title = {Towards On-Demand Heralded Single-Photon Sources via Photon Blockade},
author = {Jiangshan Tang and Lei Tang and Haodong Wu and Yang Wu and Hui Sun and Han Zhang and Tao Li and Yanqing Lu and Min Xiao and Keyu Xia},
journal= {arXiv preprint arXiv:2104.04178},
year = {2021}
}