We describe a cavity-enhanced spontaneous parametric down-conversion (CE-SPDC) source for narrowband photon pairs with filters such that over 97% of the correlated photons are in a single mode of 4.3(4) MHz bandwidth. Type-II phase matching, a tuneable-birefringence resonator, MHz-resolution pump tuning, and tuneable Fabry-Perot filters are used to achieve independent signal and idler tuning. We map the CE-SPDC spectrum using difference frequency generation to precisely locate the emission clusters, and demonstrate CE-SPDC driven atomic spectroscopy. The generated photon pairs efficiently interact with neutral rubidium, a well-developed system for quantum networking and quantum simulation. The techniques are readily extensible to other material systems.
@article{arxiv.1911.00056,
title = {Narrowband photon pairs with independent frequency tuning for quantum light-matter interactions},
author = {Vindhiya Prakash and Lorena C. Bianchet and Marc T. Cuairan and Pau Gomez and Natalia Bruno and Morgan W. Mitchell},
journal= {arXiv preprint arXiv:1911.00056},
year = {2020}
}