Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian coalesce.Especially,the robust ...Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian coalesce.Especially,the robust construction of higher-order exceptional points with more than two degenerate eigenfrequencies and eigenstates is challenging but yet worthwhile for applications.In this paper,we reconsider the formation of higher-order exceptional points through waveguide-coupled microring cavities and asymmetric backscattering.In this context,we demonstrate the influence of perturbations on the frequency splitting of the system.To generate higher-order exceptional points in a simple and robust way,a mirror-induced asymmetric backscattering approach is used.In addition to the exceptional-point enhanced sensing capabilities of such systems,also a cavity-selective sensitivity is achieved for particle sensing.The results are motivated by an effective Hamiltonian description and verified by full numerical simulations of the dielectric structure.展开更多
基金Deutsche Forschungsgemeinschaft(EXC 2147,Project ID 390858490,KL 3124/6-1,WI 1986/14-1)Open Access Publication Fund of Magdeburg University。
文摘Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian coalesce.Especially,the robust construction of higher-order exceptional points with more than two degenerate eigenfrequencies and eigenstates is challenging but yet worthwhile for applications.In this paper,we reconsider the formation of higher-order exceptional points through waveguide-coupled microring cavities and asymmetric backscattering.In this context,we demonstrate the influence of perturbations on the frequency splitting of the system.To generate higher-order exceptional points in a simple and robust way,a mirror-induced asymmetric backscattering approach is used.In addition to the exceptional-point enhanced sensing capabilities of such systems,also a cavity-selective sensitivity is achieved for particle sensing.The results are motivated by an effective Hamiltonian description and verified by full numerical simulations of the dielectric structure.
