Cooperative polariton dynamics in feedback-coupled cavities

Bimu Yao,S Kaur,W Lu,K -P Marzlin,C -M Hu,Y S Gui,X S Chen,J W Rao,Y Xiao,H Guo

doi:10.1038/s41467-017-01796-7

Abstract

The emerging field of cavity spintronics utilizes the cavity magnon polariton (CMP) induced by magnon Rabi oscillations. In contrast to a single-spin quantum system, such a cooperative spin dynamics in the linear regime is governed by the classical physics of harmonic oscillators. It makes the magnon Rabi frequency independent of the photon Fock state occupation, and thereby restricts the quantum application of CMP. Here we show that a feedback cavity architecture breaks the harmonic-oscillator restriction. By increasing the feedback photon number, we observe an increase in the Rabi frequency, accompanied with the evolution of CMP to a cavity magnon triplet and a cavity magnon quintuplet. We present a theory that explains these features. Our results reveal the physics of cooperative polariton dynamics in feedback-coupled cavities, and open up new avenues for exploiting the light–matter interactions.

Highlights

The emerging field of cavity spintronics utilizes the cavity magnon polariton (CMP) induced by magnon Rabi oscillations
The same quest is developing in the new field of cavity spintronics[18], where it is required for quantum control of collective spin dynamics[19, 20]
The magnon–photon coupling[21] produces the cavity magnon polariton (CMP)[7] in the P–M device, which is detected by using a twoport vector network analyzer (VNA) that measures the transmission coefficient S21(ω) of the P-cavity

Summary

Introduction

The emerging field of cavity spintronics utilizes the cavity magnon polariton (CMP) induced by magnon Rabi oscillations. For light coupled with quantum systems, cooperativity measures the ratio of Rabi frequency to decay rates and can be controlled by changing the photon Fock state occupation[2]. Such a collective dynamics has a drawback: a single quantum two-level system can be saturated by one photon excitation, so that adding photons enhances the Rabi frequency[2], but the magnon-photon coupling exhibits classical behavior[7] of coupled harmonic oscillators[11, 12].

Results

Conclusion