Anisotropy-Induced Quantum Interference and Population Trapping Between Orthogonal Quantum Dot Exciton States in Semiconductor Cavity Systems

TL;DR

This paper demonstrates how engineered anisotropy in quantum dot cavity systems enables control over exciton interactions, leading to entanglement, population trapping, and novel spectral features useful for quantum optics applications.

Contribution

It introduces a method to induce and control dipole-dipole coupling and population trapping in quantum dots via anisotropy in cavity systems, advancing quantum photonics capabilities.

Findings

Controlled dipole-dipole coupling modifies exciton decay rates.

Double pumping achieves population trapping and coherence preservation.

Spectral features like triplets and quintuplets enable new quantum light sources.

Abstract

We describe how quantum dot semiconductor cavity systems can be engineered to realize anisotropy-induced dipole-dipole coupling between orthogonal dipole states in a single quantum dot. Quantum dots in single-mode cavity structures as well as photonic crystal waveguides coupled to spin states or linearly polarized excitons are considered. We demonstrate pronounced dipole-dipole coupling to control the radiative decay rate of excitons and form pure entangled states in the long time limit. We investigate both field-free entanglement evolution and coherently pumped exciton regimes, and show how a double pumping scenario can completely eliminate the decay of coherent Rabi oscillations and lead to population trapping. In the Mollow regime, we explore the emitted spectra from the driven dipoles and show how a non-pumped dipole can take on the form of a spectral triplet, quintuplet, or a singlet, which has applications for producing subnatural linewidth single photons and more easily accessing regimes of high-field quantum optics and cavity-QED.