Optical activity of quantum wells

TL;DR

This paper demonstrates the optical activity in quantum wells, where the polarization of reflected light is converted due to spin-orbit effects and birefringence, with enhanced signals near exciton resonance.

Contribution

It provides the first measurement of bulk inversion asymmetry constant for light hole states in ZnSe/ZnMgSSe quantum wells, linking optical activity to structural properties.

Findings

Polarization conversion occurs in reflection from quantum wells.

Signal enhancement near light-hole exciton resonance.

Bulk inversion asymmetry constant measured as approximately 0.14 eVÅ.

Abstract

We report on the observation of optical activity of quantum wells resulting in the conversion of the light polarization state controlled by the light propagation direction. The polarization conversion is detected in reflection measurements. We show that a pure $s$-polarized light incident on a quantum well is reflected as an elliptically polarized wave. The signal is drastically enhanced in the vicinity of the light-hole exciton resonance. We show that the polarization conversion is caused by the spin-orbit splitting of the light hole states and the birefringence of the studied structure. The bulk inversion asymmetry constant $\beta_{h} \approx 0.14$ eV\AA, is determined for the ground light hole subband in a 10 nm ZnSe/ZnMgSSe quantum well.