Photon echoes using atomic frequency combs in Pr:YSO -- experiment and semiclassical theory

Published

January 30, 2023

Author(s)

Zachary Levine, Aditya N. Sharma, Kumel H. Kagalwala, Martin A. Ritter, Eli J. Weissler, Elizabeth A. Goldschmidt, Alan Migdall

Abstract

Photon echoes in rare-earth-doped crystals are studied to understand the challenges of making broadband quantum memories using the atomic frequency comb (AFC) protocol in systems with hyperfine structure. The hyperfine structure of Pr3+ poses an obstacle to this goal because frequencies associated with the hyperfine transitions change the simple picture of modulation at an externally imposed frequency. The current work focuses on the intermediate case where the hyperfine spacing is comparable to the comb spacing, a challenging regime that has recently been considered. Operating in this regime may facilitate storing quantum information over a larger spectral range in such systems. In this work, we prepare broadband AFCs using optical combs with tooth spacings ranging from 1 MHz to 16 MHz in fine steps, and measure transmission spectra and photon echoes for each. We predict the spectra and echoes theoretically using the optical combs as input to either a rate equation code or a density matrix code, which calculates the redistribution of populations. We then use the redistributed populations as input to a semiclassical theory using the frequency-dependent dielectric function. The two sets of predictions each give a good, but different account of the photon echoes.

Citation

Optics Express

Volume

31

Issue

3

Pub Type

Journals

Download Paper

https://doi.org/10.1364/OE.479872

Local Download

Keywords

Pr:YSO , quantum memory , hyperfine structure , atomic frequency comb

Citation

Levine, Z. , Sharma, A. , Kagalwala, K. , Ritter, M. , Weissler, E. , Goldschmidt, E. and Migdall, A. (2023), Photon echoes using atomic frequency combs in Pr:YSO -- experiment and semiclassical theory, Optics Express, [online], https://doi.org/10.1364/OE.479872, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=931306 (Accessed October 13, 2025)