Dynamics of Cu$_2$O Rydberg excitons -- real density matrix approach

TL;DR

This paper introduces an analytical real-density matrix approach to model two-photon absorption and emission dynamics of Cu$_2$O Rydberg excitons, aligning well with recent experimental observations.

Contribution

The paper develops a novel analytical method, the real-density matrix approach, to describe excitonic responses and dynamics in Cu$_2$O, incorporating coherence and quantum beats.

Findings

Excellent agreement with experimental data

Analytical expression for emission intensity evolution

Accounts for coherence, quantum beats, and laser power effects

Abstract

Basing on recent reliable measurements of the life- and coherence time of Cu$_2$O Rydberg excitons, we present an analytical method which enables to describe the experimental results. The real-density matrix approach (RDMA) is applied to describe two-photon absorption in Cu$_2$O through the excitonic response to the exciting fields. This approach produces an analytical expression for the emission intensity time evolution, and can be used to explain trends in reported experimental data. Our approach takes into account the effect of the coherence between the electron-hole pair and the electromagnetic fields, the quantum beats and the life- and coherence time dependence on the applied laser power. Adding a separation of slow- and rapid dynamics components we find excellent agreement with the experimental data.