Exceptional-point-enhanced rotation sensing with improved robustness and real-frequency splitting

Optical gyroscopes measure angular velocity based on the Sagnac effect. However, the resonance frequency splitting induced by this effect is proportional to the physical size of the device, which poses constraints on the integration of the system. In non-Hermitian systems, exceptional points (EPs) exhibit extreme sensitivity to small perturbations, offering great potential for the development of high-sensitivity sensors. This study proposes a non-Hermitian gyroscope design that is easy to implement and offers high degrees of freedom. In this scheme, frequency splitting can be tuned by adjusting the phase shift, while the introduction of gain enhances the magnitude of frequency splitting without inducing lasing. This mechanism offers critical support for achieving ultra-precise rotational sensing. Theoretical analysis indicates that, compared to the classical Sagnac effect, the frequency splitting enhancement can exceed seven orders of magnitude at a rotation rate of 0.01°/h.