Giant microwave–optical Kerr nonlinearity via Rydberg excitons in cuprous oxide

Pritchett, Jon D.; Gallagher, Liam A. P.; Brewin, Alistair; Wong, Horatio Q. X.; Langbein, Wolfgang; Lynch, Stephen A.; Adams, C. Stuart; Jones, Matthew P. A.

Abstract

Microwave–optical conversion is key to future networks of quantum devices, such as those based on superconducting technology. Conversion at the single quantum level requires strong nonlinearity, high bandwidth, and compatibility with a millikelvin environment. A large nonlinearity is observed in Rydberg atoms, but combining atomic gases with dilution refrigerators is technically challenging. Here, we demonstrate a strong microwave–optical nonlinearity in a cryogenic, solid-state system by exploiting Rydberg states of excitons in Cu2O. We measure a microwave–optical cross-Kerr coefficient of B0 = 0.022 ± 0.008 m V−2 at 4 K, which is several orders of magnitude larger than other solid-state systems. The results are in quantitative agreement with a nonlinear susceptibility model based on the giant microwave dipole moment between nearby excitonic states. Our results highlight the potential of Rydberg excitons for nonlinear optics and form the basis for a microwave–optical frequency converter based on Cu2O.

Citation

Pritchett, J. D., Gallagher, L. A. P., Brewin, A., Wong, H. Q. X., Langbein, W., Lynch, S. A., …Jones, M. P. A. (2024). Giant microwave–optical Kerr nonlinearity via Rydberg excitons in cuprous oxide. APL Photonics, 9(3), Article 031303. https://doi.org/10.1063/5.0192710

• Journal Article Type: Letter
• Acceptance Date: Feb 7, 2024
• Online Publication Date: Mar 1, 2024
• Publication Date: Mar 1, 2024
• Deposit Date: Apr 5, 2024
• Publicly Available Date: Apr 5, 2024
• Journal: APL Photonics
• Print ISSN: 2378-0967
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 3
• Article Number: 031303
• DOI: https://doi.org/10.1063/5.0192710
• Keywords: Computer Networks and Communications; Atomic and Molecular Physics, and Optics
• Public URL: https://durham-repository.worktribe.com/output/2378189