Deterministic coupling of a quantum emitter to surface plasmon polaritons, Purcell enhanced generation of indistinguishable single photons and quantum information processing

Abstract: Integrated photonic circuits are an integral part of all-optical and on-chip quantum information processing and quantum computer. Deterministically integrated single-photon sources in nanoplasmonic circuits lead to densely packed scalable quantum logic circuits operating beyond the diffraction limit. Here, we report the coupling efficiency of single-photon sources to the plasmonic waveguide, characteristic transmission spectrum, propagation length, decay length, and plasmonic Purcell factor. We simulated the transmission spectrum to find the appropriate wavelength for various width of the dielectric in the metal-dielectric-metal waveguide. We find the maximum propagation length of 3.98 $\mu$m for Al${2}$O${3}$ dielectric-width equal to 140 nm and coupling efficiency to be greater than 82 \%. The plasmonic Purcell factor was found to be inversely proportional to dielectric-width (w), reaching as high as 31974 for w equal to 1 nm. We also calculated quantum properties of the photons like indistinguishability and found that it can be enhanced by plasmonic-nanocavity if single-photon sources are deterministically coupled. We further, propose a scalable metal-dielectric-metal waveguide based quantum logic circuits using the plasmonic circuit and Mach-Zehnder interferometer.