Single-photon Source Of High Emission Rate Nanowires/quantum Dots Based On Microcavity Structure

As one of the core devices of quantum communication and quantum computing,single-photon source has always been a research hotspot in the field of quantum information.Semiconductor quantum dots are considered as ideal structural units for single-photon sources due to their outstanding luminescence properties,easy integration,and electric pumping.However,pure quantum dots have defects of uncontrollable luminescence direction and low emission rate,which limit their application in single-photon sources.This paper focuses on the design of high-performance quantum dots single-photon sources,adopting nanowire/quantum dot structure to realize the controllable position,size and emission direction of quantum dots,constructing metal-insulator-metal(MIM)waveguide structure resonator with plasmon-induced transparency(PIT)effect to enhances the emission rate of quantum dots.Major research achievements and innovations include:1.The luminescence properties of single-photon sources with GaAs/InGaAs nanowires/quantum dot axial structure were studied.The results show that the quantum dots can be coupled to the resonant mode of the nanowire cavity,and a Purcell factor of 5.82 is obtained in a nano wire with a diameter of 70 nm.2.Design a nanowire/quantum dot single-photon source structure based on MIM waveguide and T-shaped resonator.By adjusting the length,width and coupling spacing of the T-cavity,the PIT effect and the shift of the transmission peak are realized.When the width of the T-cavity is 10 nm,the length of the dark cavity is 325 nm,the length of the bright cavity is 240 nm,and the coupling distance is 15 nm,the quantum dot luminescence with the wavelength of 910 nm can be strongly coupled with the resonator,and the Purcell factor of nearly 900 can be obtained.3.Design a nanowire/quantum dot single-photon source structure based on MIM waveguide,U-shaped resonator and rectangular resonator.The bright and dark state are realized through coupling between the Ushaped cavity and the rectangular cavity,and the PIT effect is realized by the destructive interference between the bright and dark state.By optimizing material and structural parameters,the Purcell factor can reach up to nearly 2000.