Cavity-enhanced simultaneous dressing of quantum dot exciton and biexciton states

TL;DR

This paper demonstrates the simultaneous dressing of quantum dot exciton and biexciton states within a high-Q cavity, revealing strong-field effects and spectral features explained by dressed state theory and a polaron master equation.

Contribution

It introduces a method to coherently control both exciton and biexciton states in a quantum dot using cavity-enhanced resonant excitation, with theoretical modeling of the spectral phenomena.

Findings

Observation of strong-field splitting in emission lines

Spectral tuning via cavity-laser detuning affects Rabi oscillations

Theoretical predictions match experimental spectral features

Abstract

We demonstrate the simultaneous dressing of both vacuum-to-exciton and exciton-to-biexciton transitions of a single semiconductor quantum dot in a high-Q micropillar cavity, using photoluminescence spectroscopy. Resonant two-photon excitation of the biexciton is achieved by spectrally tuning the quantum dot emission with respect to the cavity mode. The cavity couples to both transitions and amplifies the Rabi-frequency of the likewise resonant cw laser, driving the transitions. We observe strong-field splitting of the emission lines, which depend on the driving Rabi field amplitude and the cavity-laser detuning. A dressed state theory of a driven 4-level atom correctly predicts the distinct spectral transitions observed in the emission spectrum, and a detailed description of the emission spectra is further provided through a polaron master equation approach which accounts for cavity coupling and acoustic phonon interactions of the semiconductor medium.