Direct measurement of the lifetime and coherence time of Cu2O Rydberg excitons

TL;DR

This study directly measures the lifetimes and coherence times of Cu2O Rydberg excitons, revealing their potential for coherent quantum manipulation and confirming the absence of inhomogeneous broadening.

Contribution

It provides the first direct measurements of Rydberg exciton lifetimes and coherence times in Cu2O, demonstrating their suitability for quantum engineering applications.

Findings

Lifetimes follow Rydberg scaling law

Observation of long-lived coherent oscillations

Good agreement between lifetime and coherence time measurements

Abstract

Rydberg states of excitons are promising quantum objects to engineer giant nonlinearities in a solid-state system. For this purpose, a deeper understanding of the dynamics of Rydberg excitons and of their potential for coherent manipulation becomes important. We report experimental results where two-photon absorption is resonant with various Rydberg states of excitons in copper oxide and we detect their emission dynamics on a streak camera with sub-picosecond resolution. This technique enables the direct measurement of the Rydberg states lifetimes, which are in good agreement with the expected Rydberg scaling law. Moreover, we observe several intriguing dynamics including the presence of long-lived coherent oscillations. Finally, we independently measure the coherence time of the Rydberg states using a modified Michelson interferometer and find a good agreement with the coherent oscillations detected in the exciton emission dynamics. The lifetimes also reveal the absence of inhomogeneous broadening in the current high-precision spectroscopic data for the S series, which together with the presence of significant coherence time confirms the suitability of the system for coherent engineering.