Dephasing of quantum dot exciton polaritons in electrically tunable nanocavities

TL;DR

This study investigates how temperature and excitation power affect the coherence and dephasing of quantum dot polaritons in tunable nanocavities, combining experiments with theoretical analysis.

Contribution

It provides the first detailed analysis of dephasing mechanisms in electrically tunable quantum dot microcavities, highlighting phonon and excitation-induced effects.

Findings

Dephasing rate depends linearly on temperature at low excitation levels.

Higher excitation induces additional dephasing due to environment coupling.

Temperature and excitation power significantly influence polariton coherence.

Abstract

We experimentally and theoretically investigate dephasing of zero dimensional microcavity polaritons in electrically tunable single dot photonic crystal nanocavities. Such devices allow us to alter the dot-cavity detuning in-situ and to directly probe the influence on the emission spectrum of varying the incoherent excitation level and the lattice temperature. By comparing our results with theory we obtain the polariton dephasing rate and clarify its dependence on optical excitation power and lattice temperature. For low excitation levels we observe a linear temperature dependence, indicative of phonon mediated polariton dephasing. At higher excitation levels, excitation induced dephasing is observed due to coupling to the solid-state environment. The results provide new information on coherence properties of quantum dot microcavity polaritons.