Optical manipulation of a magnon-photon hybrid system

TL;DR

This paper presents an all-optical technique to control magnetization in a YIG sphere using a frequency comb and magnon-photon coupling, enabling ultrafast magnetization manipulation with potential applications in optomagnetic devices.

Contribution

It introduces a novel all-optical method for manipulating magnetization in YIG using frequency combs and magnon-photon coupling, overcoming radiation damping issues.

Findings

Achieved ultrafast control of magnetization via laser polarization and intensity modulation.

Demonstrated strong magnon-photon coupling regime in microwave cavities.

Measured a second-order susceptibility of approximately 10^{-7} cm^2/MW for YIG.

Abstract

We demonstrate an all-optical method for manipulating the magnetization in a 1-mm YIG (yttrium-iron-garnet) sphere placed in a $\sim0.17\,$T uniform magnetic field. An harmonic of the frequency comb delivered by a multi-GHz infrared laser source is tuned to the Larmor frequency of the YIG sphere to drive magnetization oscillations, which in turn give rise to a radiation field used to thoroughly investigate the phenomenon. The radiation damping issue that occurs at high frequency and in the presence of highly magnetizated materials, has been overcome by exploiting magnon-photon strong coupling regime in microwave cavities. Our findings demonstrate an effective technique for ultrafast control of the magnetization vector in optomagnetic materials via polarization rotation and intensity modulation of an incident laser beam. We eventually get a second-order susceptibility value of $\sim10^{-7}$ cm$^2$/MW for single crystal YIG.