Inducing electron spin coherence in GaAs quantum well waveguides: Spin coherence without spin precession

TL;DR

This paper demonstrates that electron spin coherence can be induced in GaAs quantum well waveguides using light-hole transitions without magnetic fields, and detects it through quantum interference effects in nonlinear optical responses.

Contribution

It introduces a method to induce and detect electron spin coherence without magnetic fields, using optical transitions and quantum interference in quantum wells.

Findings

Spin coherence is induced without external magnetic fields.

Quantum interference effects reveal the induced spin coherence.

A simple few-level model explains the experimental results.

Abstract

Electron spin coherence is induced via light-hole transitions in a quantum well waveguide without either an external or internal DC magnetic field. In the absence of spin precession, the induced spin coherence is detected through effects of quantum interference in the spectral domain coherent nonlinear optical response. We interpret the experimental results qualitatively using a simple few-level model with only the optical transition selection rule as its basic ingredients.