Geometry Optimization of Split Ring Resonator for Terahertz Magnon-Photon Coupling

Abstract

Magnon-photon coupling has been studied to develop effective quantum transducers and long-lifetime quantum memories. In order to achieve magnon-photon coupling, various cavity structures and magnetic materials have been used to excite a photon and magnon of a certain frequency. However, most of the studies so far have remained in the gigahertz (GHz) frequency range, so it is hard to achieve magnon-photon coupling in the terahertz (THz) range which is one of the efficient ways to make a high-temperature quantum regime. Here, we investigate the geometry optimization of a simple cavity structure, a split ring resonator (SRR) in the terahertz frequency range by using simulation as well as the experiment. The simulation shows that the efficiency and resonance frequency are varied by adjusting the geometric length and gap of the SRR. The simulation results are confirmed experimentally by using terahertz time-domain spectroscopy. This work paves the way for a controllability of terahertz photon resonator with high efficiency for high temperature quantum magnon-photon coupling experiments.