Optimizing Four-Wave Mixing in Rydberg Atoms for Microwave-Optical Conversion

TL;DR

This paper investigates microwave-to-optical conversion using four-wave mixing in Rydberg atoms, demonstrating high efficiency in both resonant and off-resonant configurations, with off-resonant being more practical for broader input ranges.

Contribution

The study provides a detailed analysis of dark states and limitations in four-wave mixing in Rydberg atoms, highlighting the advantages of off-resonant configurations for efficient photon conversion.

Findings

Both configurations achieve near-unit conversion efficiency.

Off-resonant configuration is more robust across input microwave powers.

Microwave-induced fluorescence limits all-resonant frequency mixing.

Abstract

We perform a numerical and analytical investigation of microwave-to-optical conversion based on four-wave mixing in Rydberg atoms. Our work demonstrates that both all-resonant and off-resonant frequency-mixing configurations achieve near-unit photon conversion efficiencies. We review the conditions that can lead to the presence of two possible dark states. We find that for both configurations, one of the dark states can be detrimental at high microwave powers, and show that an additional limitation to all-resonant frequency mixing is microwave-induced fluorescence. Finally, we confirm that the off-resonant configuration is more appropriate as it allows for efficient photon conversion on a wider range of input microwave intensities with reduced total power of the auxiliary fields.