Unidirectional Reflectionlessness And Quantum Entanglement In Surface Plasmonic Waveguide Systems

Surface plasmon is a special electromagnetic oscillation mode at the interface between metal and dielectric and became a new ideal carrier of quantum information due to its unique transmission characteristics.This paper investigate the transmission characteristics of surface plasmon in waveguide system coupled with resonators and the specific research contents are as follows:First,we construct a model consist of two interacting quantum dots side coupling with waveguide to research the unidirectional reflectionlessness of surface plasmon in waveguide,the result indicate that when phase shift between two quantum dots θ =0.95003π and 1.04997π,unidirectional reflectionlessness is achieved at 1540 nm and 1585 nm,respectively.In addition,by studying the influence of different parameters on the reflection spectrum,it’s proved that the system can achieve unidirectional reflectionlessness in a wide range of quantum dot-waveguide coupling strength η,loss rate Γ of quantum dot,coupling strength G and phase shift θ between quantum dots.Different from models which need to change the phase shift between quantum dots to change the position of unidirectional reflectionlessness,this system has the characteristic that the position of unidirectional reflectionlessness can be changed only by change coupling strength between quantum dots.Then,we construct a three-cavity array system composed of three decay plasmon cavities and a waveguide to research unidirectional reflectionlessness and non-reciprocal entanglement of surface plasmon in waveguide,the result show that with the adapted system parameters,unidirectional reflectionlessness is achieved at the wavelength of 1539 nm and 1554 nm when θ = 0.983π and 1545 nm and 1562 nm when θ = 1.017π,respectively.Next we explore the influence of different parameters on the reflection spectrum.It is proved that the system can achieve dual-band unidirectional reflectionlessness in the wide range of the cavity-waveguide coupling strength η,decay rate Γ of cavity,coupling strength g within the double-cavity array and phase shift θ between single cavity and double-cavity array.In addition,it’s be confirmed that non-reciprocal entanglement can be realized by calculating the concurrence between each two cavities in the system.