Photo-thermal transitions of magneto-excitons in quantum wells

TL;DR

This study investigates how terahertz radiation affects magnetoexcitons in GaAs/AlGaAs quantum wells by monitoring photoluminescence changes, revealing resonant absorption and photo-thermal conversion mechanisms.

Contribution

It demonstrates resonant THz absorption by magnetoexcitons and elucidates the photo-thermal conversion process in quantum wells.

Findings

Resonant THz absorption observed in magnetoexcitons.

PL-quenching peaks at heavy hole $1s\to 2p^+$ resonance.

Photo-thermal conversion from heavy to light hole excitons identified.

Abstract

By monitoring changes in excitonic photoluminescence (PL) that are induced by terahertz (THz) radiation, we observe resonant THz absorption by magnetoexcitons in GaAs/AlGaAs quantum wells. Changes in the PL spectrum are explored as a function of temperature and magnetic field, providing insight into the mechanisms which allow THz absorption to modulate PL. The strongest PL-quenching occurs at the heavy hole $1s\to 2p^+$ resonance where heavy hole excitons are photo-thermally converted into light hole excitons.