Seminarium Fizyki Ciała Stałego

In the regime of strong light-matter coupling, polariton modes are formed that are hybrid light-matter excitations sharing properties of both, a cavity mode and a matter mode. In the recent decade, ferromagnetic spin waves (magnons) coupling to cavity photons was intensively researched in the microwave range (few to tens of GHz). These studies are motivated by applications for quantum devices, due to the hybrid nature of magnon-polaritons, and interesting physics, like the observation of the dissipative coupling. However, magnon-polaritons can also be observed at much higher frequencies using antiferromagnetic materials, which have magnons in the THz range. We report on the observation of magnon-polaritons at THz frequencies, and how we use light-matter coupling to achieve cavity-mediated coupling of magnons in distant crystals, and cavity-mediated magnon-phonon coupling.