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arXiv · 2109.09614

Microwave-optical coupling via Rydberg excitons in cuprous oxide

Liam A. P. Gallagher·Joshua P. Rogers·Jon D. Pritchett·Rajan A. Mistry·Danielle Pizzey·Charles S. Adams·Matthew P. A Jones·Peter Grünwald·Valentin Walther·Chris Hodges·Wolfgang Langbein·Stephen A. Lynch
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Abstract

We report exciton-mediated coupling between microwave and optical fields in cuprous oxide (Cu$_2$O) at low temperatures. Rydberg excitonic states with principal quantum number up to $n=12$ were observed at 4~K using both one-photon (absorption) and two-photon (second harmonic generation) spectroscopy. Near resonance with an excitonic state, the addition of a microwave field significantly changed the absorption lineshape, and added sidebands at the microwave frequency to the coherent second harmonic. Both effects showed a complex dependence on $n$ and angular momentum, $l$. All of these features are in semi-quantitative agreement with a model based on intraband electric dipole transitions between Rydberg exciton states. With a simple microwave antenna we already reach a regime where the microwave coupling (Rabi frequency) is comparable to the nonradiatively broadened linewidth of the Rydberg excitons. The results provide a new way to manipulate excitonic states, and open up the possibility of a cryogenic microwave to optical transducer based on Rydberg excitons.

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Liam A. P. Gallagher, Joshua P. Rogers, Jon D. Pritchett, Rajan A. Mistry, Danielle Pizzey, Charles S. Adams, Matthew P. A Jones, Peter Grünwald, Valentin Walther, Chris Hodges, Wolfgang Langbein, Stephen A. Lynch. 2021-09-20. Microwave-optical coupling via Rydberg excitons in cuprous oxide. https://doi.org/10.1103/physrevresearch.4.013031

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