Transition from Jaynes-Cummings to Autler-Townes ladder in a quantum dot-microcavity system

TL;DR

This paper investigates the transition from quantum Jaynes-Cummings ladder to semi-classical Autler-Townes ladder in a strongly-coupled quantum dot-microcavity system under coherent driving, revealing the intermediate regime's unique spectral features.

Contribution

It experimentally and theoretically characterizes the intermediate excitation regime where laser dressing creates a ladder of states bridging quantum and semi-classical behaviors.

Findings

Observation of injection pulling of polariton branches by an external laser

Identification of a maximum in resonance fluorescence as a signature of the intermediate regime

Signatures of laser-dressed Jaynes-Cummings ladder in the system's spectra

Abstract

We study experimentally and theoretically a coherently-driven strongly-coupled quantum dot-microcavity system. Our focus is on physics of the unexplored intermediate excitation regime where the resonant laser field dresses a strongly-coupled single exciton-photon (polariton) system resulting in a ladder of laser-dressed Jaynes-Cummings states. In that case both the coupling of the emitter to the confined light field of the microcavity and to the light field of the external laser are equally important, as proved by observation of injection pulling of the polariton branches by an external laser. This intermediate interaction regime is of particular interest since it connects the purely quantum mechanical Jaynes-Cummings ladder and the semi-classical Autler-Townes ladder. Exploring the driving strength-dependence of the mutually coupled system we establish the maximum in the resonance fluorescence signal to be a robust fingerprint of the intermediate regime and observe signatures indicating the laser-dressed Jaynes-Cummings ladder. In order to address the underlying physics we excite the coupled system via the matter component of fermionic nature undergoing saturation - in contrast to commonly used cavity-mediated excitation.