We propose a criterion to classify and compare sources of single photons: the p-norm of their kth-order photon correlations. While ideally one should use the uniform norm with p→∞, in practice, the 3-norm already allows a meaningful comparison and shows the serious limitations of the usual criterion based on the second order correlation g(2) only. We apply this new criterion to a large family of popular single photon sources and show that some of them do not, in fact, qualify for this function. The best sources from our selections consist of a cascade of two-level systems, improving on the otherwise standard low-power resonant excitation of a single two-level system.
@article{arxiv.1610.06126,
title = {Criterion for Single Photon Sources},
author = {Juan Camilo López Carreño and Eduardo Zubizarreta Casalengua and Elena del Valle and Fabrice P. Laussy},
journal= {arXiv preprint arXiv:1610.06126},
year = {2016}
}