Optical Field Properties Based On Waveguide QED

All-optical quantum devices such as single-photon quantum switches and quantum diodes are some of core components for integrated and large-scale quantum networks.They also become the focus of the field of photon transport.Waveguide quantum electrodynamics(waveguide QED)and cavity quantum electrodynamics(cavity QED)are two important systems to enhance light-matter interactions,which play an important role in the study of photon transport.In this paper,we combine the advantages of waveguide QED and cavity QED to analyze,simulate and discuss the influence of two coupled cavity-QED subsystems interact with a 1D waveguide on the single-photon scattering properties via real space method.It is found that the two coupled cavity-QED subsystems have a significant effect on the single-photon transport,resulting in more transmission and reflection peaks and other nonlinear phenomena.In addition,based on the nonlinear optical phenomena,we propose to realize a single-photon optical switch.Secondly,we study several atoms chirally coupled to the photons in a 1D waveguide.By using the transfer matrix method,we simulate the single-photon transmission spectrum for single or multiple V-type atoms coupled with a 1D waveguide.It is found that the appropriate choice of the coupling rates between atomic transitions and photons and the selection of the special energy level structure of atoms will lead to the nonreciprocal transmission of the system.On the basis of it,we propose to realize single-photon quantum diodes.We hope that our results may provide some contribution to the field of quantum information.