Sub-Poissonian light generation in a coupled quantum dot-photonic molecule system

Abstract

We theoretically investigate the photon statistics in a cavity quantum electrodynamics system of a single quantum dot (QD) coupled to photonic molecule. Our previous work [Wen Zhang et.al, Phys. Rev. A 89, 043832 (2014)] has shown that QD-bimodal cavity system can generate ultrastrongly sub-Poissonian light by regulating the ratio between driving strengths of two cavity modes. Here we study two coupled single-mode nanocavities with a QD coupling to one of them as a photonic molecule system. Statistical character of photon emission is presented by evaluating the zero-delay secondorder correlation function g²(0). When both cavities with/without QD are driven, the sub-Poissonian character can be optimized by regulating the ratio between driving strengths of each cavities. We also present the dependences of other system parameters on the photon statistics. The physical mechanism of both effects is to optimize the combination of super-Poissonian and coherent light which results in sub-Poissonian light generation. As a result g²(0) can be reduced up to several orders of magnitude compared with the QD coupled one-mode-cavity system.