Antiferromagnetic Cavity Magnon Polaritons in Collinear and Canted Phases of Hematite

Cavity spintronics explores light-matter interactions at the interface between spintronic and quantum phenomena. Until now, studies have focused on hybridization magnons in ferromagnets cavity photons. Here, we realize antiferromagnetic magnon polaritons. Hybridization arises from interaction of collective spin motion single hematite crystals (\ensuremath{\alpha}-${\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$) microwave field integrated cavities operating 18 45 GHz. We show theoretically experimentally that photon-magnon coupling collinear phase is mediated by dynamic N\'eel vector weak magnetic moment canted measuring across Morin transition. strength, $\stackrel{~}{g}$, scales with anisotropy Dzyaloshinskii-Moriya phase. reach strong-coupling regime both (cooperativity C > 70 for selected modes 300 K) noncollinear phases (C 4 150 K), thus, towards coherent information-exchange-harnessing These results provide evidence a generic strategy to achieve polaritons antiferromagnets different symmetries, opening materials.