Coherent Population Trapping of Electron Spins in a Semiconductor

TL;DR

This paper demonstrates coherent population trapping of electron spins in high-purity GaAs, showing potential for quantum optics applications in semiconductor systems.

Contribution

It reports the first observation of coherent population trapping in GaAs, using a lambda system of Zeeman states and a three-level density-matrix model.

Findings

Pronounced dip in photoluminescence at two-photon resonance

Consistent with a steady-state three-level density-matrix model

Indicates potential for EIT-type experiments in semiconductors

Abstract

In high-purity n-type GaAs under strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various EIT-type experiments.