Strong to ultra-strong coherent coupling measurements in a YIG/cavity system at room temperature

TL;DR

This paper experimentally investigates the transition from strong to ultra-strong coupling regimes at room temperature in a YIG/cavity system, demonstrating high coupling rates and analyzing polaritonic branches with simulations.

Contribution

It reports the first detailed experimental study of strong to ultra-strong coupling in a room-temperature YIG/cavity system with reconfigurable 3D cavities.

Findings

Coupling rates range from 12% to 59% of cavity frequency.

Excellent agreement between experimental results and finite element simulations.

Analysis highlights considerations for polaritonic branch interpretation in focused RF fields.

Abstract

We present an experimental study of the strong to ultra-strong coupling regimes at room temperature in frequency-reconfigurable 3D re-entrant cavities coupled with a YIG slab. The observed coupling rate, defined as the ratio of the coupling strength to the cavity frequency of interest, ranges from 12% to 59%. We show that certain considerations must be taken into account when analyzing the polaritonic branches of a cavity spintronic device where the RF field is highly focused in the magnetic material. Our observations are in excellent agreement with electromagnetic finite element simulations in the frequency domain.