Nonlinear level attraction of cavity axion polariton in antiferromagnetic topological insulator
Yang Xiao, Huaiqiang Wang, Dinghui Wang, Ruifeng Lu, Xiaohong Yan, Hong Guo, C.‐M. Hu, Ke Xia, Haijun Zhang, Dingyu Xing
Abstract
Strong coupling between cavity photons and elementary excitations in condensed matters boosts the field of light-matter interaction and generates several exciting subfields, such as cavity optomechanics and cavity magnon polariton. Axion quasiparticles, emerging in topological insulators, were predicted to strongly couple with the light and generate the so-called axion polariton. Here we demonstrate that there arises a gapless level attraction (LA) of cavity axion polariton in an antiferromagnetic topological insulator, which originates from the high-order interaction between the axion and the odd-order resonance of a cavity. Such a novel coupling mechanism is essentially different from conventional LAs with the linear-order interaction. Our results open up promising roads for exploring the axion polariton with cavity technologies.