We experimentally study a broadband implementation of the atomic frequency comb (AFC) rephasing protocol with a cryogenically cooled Pr3+:Y2SiO5 crystal. To allow for storage of broadband pulses, we explore a novel regime where the input photonic bandwidth closely matches the inhomogeneous broadening of the material (∼5GHz), thereby significantly exceeding the hyperfine ground and excited state splitting (∼10MHz). Through an investigation of different AFC preparation parameters, we measure a maximum efficiency of 10% after a rephasing time of 12.5ns. With a suboptimal AFC, we witness up to 12 rephased temporal modes.
@article{arxiv.2102.13113,
title = {Gigahertz-Bandwidth Optical Memory in Pr$^{3+}$:Y$_2$SiO$_5$},
author = {M. Nicolle and J. N. Becker and C. Weinzetl and I. A. Walmsley and P. M. Ledingham},
journal= {arXiv preprint arXiv:2102.13113},
year = {2021}
}