Dynamics of polariton-magnon coupling in CrSBr

CrSBr, a 2D magnetic semiconductor that hosts excitons that are strongly correlated to the underlying magnetic order has recently garnered much attention in the context of van der Waals magnets. Owing to the large dielectric constant, CrSBr hosts self-hybridized exciton-polaritons [1]. Here we report the fingerprint of magnon oscillations on the different polaritonic states over a broad spectral range. The dependence of the magnon oscillation frequency and amplitude on incident photon density and magnetic field using transient absorption measurements will be presented. The lifetime of the magnon oscillation is found to decrease at higher incident photon density owing to increased exciton and magnon density. The effect of sample geometry on the exciton-magnon coupling and magnon energy will also be discussed. The interplay between electron excitations and magnetic order in CrSBr makes it an interesting candidate for the opto-spintronic and quantum transduction applications.