Nonreciprocal single-photon scattering in giant-spin-ensemble–waveguide magnonics
Xin Wang, Qing‐Yang Qiu, Kai‐Wei Huang, Hao Xiong
Abstract
We study nonreciprocal single-photon scattering in a giant-spin-ensemble (GSE)--waveguide magnonics system where the GSE constructed by a yttrium iron garnet sphere interacts twice with the waveguide via two separated coupling points. It is shown that the generation of nonreciprocity arises from the synergy of the breaking of time-reversal symmetry induced by the chiral coupling and the intrinsic dissipation of the magnon mode in the case of a single waveguide. The accumulated phase caused by the photon propagating between coupling points can be a powerful tool to control nonreciprocity due to quantum interference effects. Compared to the Markovian regime, single-photon transmission exhibits peculiarly nonreciprocal properties in the non-Markovian regime. Multiple narrow nonreciprocal transmission windows are observed. Non-Markovianity can break the decoupling phenomenon of the Markovian regime and non-Markovianity-induced nonreciprocity is demonstrated. We extend the study of nonreciprocity to the GSE coupled to a double-waveguide structure to explore the design of quantum devices. A high-efficiency and tunable multifrequency single-photon targeted router and circulator with narrow operational bandwidth are achieved. Our results provide an effective avenue for single-photon manipulation and have potential applications in designing magnon-based quantum devices and constructing an integrated quantum network.