Nanoscatterer-mediated frequency combs in cavity optomagnonics

In non-Hermitian systems, the eigenfrequency of resonance modes coalesces at the exceptional points (EPs) in the frequency domain, leading to extraordinary parametric sensitivity. In this study, the controllable generation of high-order sidebands and frequency combs is investigated in the optomagnonical system, which comprises a single optomagnonical resonator coupled with two nanotips. Exploiting the scattering induced by the nanotips, the EPs periodically emerge as the relative angle of the two nanoscatterers in the system is tuned, and the sidebands' spectrum could be modified significantly. Moreover, we uncover that the driving field plays an essential role in controlling the orders and amplitudes of the sidebands. In particular, the generation of the frequency combs can be controlled by the external magnetic field, which determines the precession frequency of the spin. This study provides a potential method to manipulate the optical nonlinearity and to apply this method in the fields of optical communications and information processing.