Hyperfine Structure and Optical Pumping in Three-Photon Rydberg EIT

We present a comprehensive framework for three-photon Rydberg Electromagnetically Induced Transparency (EIT) in ⁸⁵Rb vapor, accounting for hyperfine-structure (HFS) and optical-pumping effects. While traditional models often employ simplified few-level schemes (such as 10-level [1] and 5-level [2] models), they frequently fail to capture nuances that are experimentally observed in Rydberg-EIT spectra in vapor cells. In our complete model, we consider the 5S_1/2-5P_1/2-5D_3/2-25F_5/2 3-photon Rydberg-EIT cascade, including partial decay via 5P_3/2. The state space has 108 magnetic sublevels, which are coupled through coherent interactions and various spontaneous-decay channels. Using a Quantum Monte Carlo Wave-Function (QMCWF) approach [3,4], we find approximate solutions to the large Lindblad master equation. Interpretations of experimental EIT maps, based on theoretical model spectra and related observables, are more complete and accurate than those obtained from truncated state spaces. We specifically analyze the impact of laser polarization, beam size, and beam propagation configuration. Our study demonstrates that accurate modeling of HFS and optical pumping is essential in complex Rydberg-EIT systems, which underpin numerous emerging quantum technologies and devices. This work was supported by NSF Award Number PHY-2110049.

 

References:

[1] A. Duspayev and G. Raithel, Phys. Rev. A 111, 032821 (2025).

[2] N. Thaicharoen, K. R. Moore, D. A. Anderson, R. C. Powel, E. Peterson, and G. Raithel, Electromagnetically induced transparency, absorption, and microwave-field sensing in a Rb vapor cell with a three-color all-infrared laser system, Phys. Rev. A 100, 063427 (2019).

[3] Y. Xue, L. Hao, Y. Jiao, X. Han, S. Bai, J. Zhao, and G. Raithel, Rydberg electromagnetically induced transparency in a large Hilbert space, Phys. Rev. A 99, 053426 (2019).

[4] L. Zhang, S. Bao, H. Zhang, G. Raithel, J. Zhao, L. Xiao, and S. Jia, Interplay between optical pumping and Rydberg EIT in magnetic fields, Opt. Express 26, 29931 (2018).