Abstract

Magnons have recently emerged as promising candidates for quantum technologies, including sensing and transduction. Developing these applications requires quantum-coherent methods for probing magnons. In this talk, I will present our theoretical advancements in using inelastic scattering of optical photons by magnons, known as Brillouin light scattering (BLS), as a tool for probing quantum properties of magnons. First, I will introduce a protocol for performing full quantum state tomography of long-wavelength magnons. We showed that quantum coherence can be measured even at a signal-to-noise ratio (SNR) of 1. For an optomagnonic waveguide based on Yttrium Iron Garnet (YIG), we found the expected SNR to be around 0.2–0.3. I will then discuss strategies to circumvent this limitation. Subsequently, I will present our recent findings on analyzing BLS from quantum skyrmions. Specifically, we show that the optical output spectrum exhibits features that can be strong experimental indicators of skyrmions displaying non-classical behavior.