Signatures of Quantum Coherence in Rydberg Excitons

TL;DR

This paper demonstrates quantum coherence effects in bulk Cu$_2$O Rydberg excitons, revealing dressed states and low dephasing, advancing semiconductor quantum technology control.

Contribution

It uncovers quantum coherent phenomena in bulk semiconductor Rydberg excitons, showing dressed states and minimal dephasing with a single laser source.

Findings

Observation of dressed states in Rydberg excitons

Low pure dephasing in the system

Emergence of quantum coherence effects in bulk material

Abstract

Coherent optical control of individual particles has been demonstrated both for atoms and semiconductor quantum dots. Here we demonstrate the emergence of quantum coherent effects in semiconductor Rydberg excitons in bulk Cu$_2$O. Due to the spectral proximity between two adjacent Rydberg exciton states, a single-frequency laser may pump both resonances with little dissipation from the detuning. As a consequence, additional resonances appear in the absorption spectrum that correspond to dressed states consisting of two Rydberg exciton levels coupled to the excitonic vacuum, forming a V-type three-level system, but driven only by one laser light source. We show that the level of pure dephasing in this system is extremely low. These observations are a crucial step towards coherently controlled quantum technologies in a bulk semiconductor.