Resonant two-photon excitation of 1s paraexcitons in Cuprous Oxide

TL;DR

This study demonstrates resonant two-photon excitation of paraexcitons in Cuprous Oxide, revealing their population dynamics and suggesting a promising method for achieving Bose-Einstein condensation of paraexcitons.

Contribution

It introduces a resonant two-photon excitation technique for paraexcitons and analyzes their dynamics in a harmonic trap, advancing the understanding of exciton generation mechanisms.

Findings

Paraexcitons are created directly via resonant two-photon excitation.

Orthoexcitons mainly form through Auger processes.

Two colliding pulses produce weaker luminescence than single-beam excitation.

Abstract

We have created paraexcitons in Cuprous Oxide via resonant two-photon generation, and examined their population dynamics by means of time-correlated single photon detection. Confining the excitons to a constant volume in a harmonic potential trap made with inhomogeneous applied stress along the [001] axis, we find that paraexcitons are created directly, and orthoexcitons appear primarily through the well-known excitonic Auger process. Hot excitons are also created via a three-photon process when the IR laser is non-resonant. Also we generate excitons with two colliding pulses, and the luminescence is weaker than that from one beam excitation with same total laser power. These results show that resonant one-beam two-photon generation of paraexcitons is a promising way to pursue Bose-Einstein condensation of paraexcitons.