Purcell enhanced single-photon emission from a quantum dot coupled to a truncated Gaussian microcavity

Abstract

Purcell enhancement of quantum dot (QD) single-photon emission and increased device brightness have been demonstrated with various types of microcavities. Here, we present the first realization of a truncated Gaussian-shaped microcavity coupled to a QD. The implementation is based on wet-chemical etching and epitaxial semiconductor overgrowth. The cavity modes and their spatial profiles are experimentally studied and agree well with simulations. The fundamental mode wavelength with Q-factors around 6000 and a small polarization splitting of 29 μeV can be reproducibly controlled via fabrication design, enabling the adaption of the cavity to a specific QD. Finally, transitions of a QD inside a cavity are tuned on and off resonance via temperature tuning. A reduced decay time by a factor above 3 on resonance clearly indicates Purcell enhancement while second-order correlation measurements of g(2)(0) = 0.057 prove that the QDs single-photon characteristic is preserved.