Mode Interference Effect in Optical Emission of Quantum Dots in Photonic Crystal Cavities

Abstract

Radiation properties of a pointlike source of light, such as a molecule or a semiconductor quantum dot, can be tailored by modifying its photonic environment. This phenomenon lies at the core of cavity quantum electrodynamics (CQED). Quantum dots in photonic crystal microcavities have served as a model system for exploring the CQED effects and for the realization of efficient single-photon quantum emitters. Recently, it has been suggested that quantum interference of the exciton recombination paths through the cavity and free-space modes can significantly modify the radiation. In this work, we report an unambiguous experimental observation of this fundamental effect in the emission spectra of site-controlled quantum dots positioned at prescribed locations within a photonic crystal cavity. The observed asymmetry in the polarization-resolved emission spectra strongly depends on the quantum dot position, which is confirmed by both analytical and numerical calculations. We perform quantum interferometry in the near-field zone of the radiation, retrieving the overlap and the position-dependent relative phase between the interfering free-space and cavity-mode-mediated radiative decays. The observed phenomenon is of importance for realization of photonic-crystal light emitters with near unity quantum efficiency. Our results suggest that the full description of light-matter interaction in the framework of CQED requires a modification of the conventional quantum master equation by also considering the radiation mode interference.12 MoreReceived 20 October 2021Revised 12 February 2022Accepted 13 April 2022Corrected 22 June 2022DOI:https://doi.org/10.1103/PhysRevX.12.021042Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCavity quantum electrodynamicsLight-matter interactionNanophotonicsOpen quantum systemsPhotonic crystalsPhotonicsQuantum description of light-matter interactionQuantum interference effectsSingle photon sourcesPhysical SystemsQuantum cavitiesQuantum dotsTechniquesFinite-difference time-domain methodFinite-element methodInterferometryOptical spectroscopyPhotoluminescenceQuantum master equationTime-resolved photoluminescenceCondensed Matter, Materials & Applied PhysicsAtomic, Molecular & OpticalGeneral Physics