Higher-order anapole-exciton strong coupling in nested Si-based hybrid systems

Higher-order anapoles have wide prospects in nonlinear optics and nanolasers due to their narrow resonances and strong energy localization. However, strong coupling involving higher-order anapoles has not been explored yet. In this work, we theoretically propose two Si-based hybrid systems consisting of a nested nanodisk-ring of Si and WSe₂ to acquire strong coupling of higher-order anapoles with excitons. By tuning the structural parameters of the hybrid system with a Si nanoring inserted with a WSe₂ nanodisk, the excited first-, second-, and third-order anapoles of the hybrid system all strongly couple with the excitons of the WSe₂ nanodisk, leading to large Rabi splittings of 83.92, 90.95, and 78.53 meV, respectively. Furthermore, strong coupling behaviors of the excited first- and second-order anapoles of the hybrid system with the excitons of the WSe₂ nanoring are also achieved in the hybrid system with a Si nanodisk surrounded by a WSe₂ nanoring, with corresponding Rabi splittings of 191.3 and 189.1 meV. Our work opens a new direction for the research on higher-order anapoles and provides a promising outlook for high-performance strong coupling devices.