Coherent multi-mode conversion from microwave to optical wave via a magnon-cavity hybrid system

TL;DR

This paper demonstrates experimentally that a magnon-cavity hybrid system can coherently convert multiple microwave modes into optical waves, with efficiency influenced by YIG sphere size and positioning, advancing quantum communication technologies.

Contribution

It introduces a multi-mode microwave-to-optical conversion method using a YIG-based magnon-cavity system, highlighting the role of YIG size and placement in optimizing efficiency.

Findings

Multi-mode conversion achieved via collective spin excitation in YIG.

YIG sphere size critically affects conversion efficiency.

YIG position within the cavity influences coupling strength.

Abstract

Coherent conversion from microwave to optical wave opens new research avenues towards long distant quantum network covering quantum communication, computing, and sensing out of the laboratory. Especially multi-mode enabled system is essential for practical applications. Here we experimentally demonstrate coherent multi-mode conversion from the microwave to optical wave via collective spin excitation in a single crystal yttrium iron garnet (YIG, Y3Fe5O12) which is strongly coupled to a microwave cavity mode in a three-dimensional rectangular cavity. Expanding collective spin excitation mode of our magnon-cavity hybrid system from Kittel to multi magnetostatic modes, we verify that the size of YIG sphere predominantly plays a crucial role for the microwave-to-optical multi-mode conversion efficiency at resonant conditions. We also find that the coupling strength between multi magnetostatic modes and a cavity mode is manipulated by the position of a YIG inside the cavity. It is expected to be valuable for designing a magnon hybrid system that can be used for coherent conversion between microwave and optical photons.