Imaging spatial distributions of laser-induced charge and spin in GaAs∕AlGaAs two-dimensional electron gas by pump-probe second harmonic generation

Abstract

We report the spatial intensity distributions of the laser-induced charge and spin polarizations in GaAs∕AlGaAs two-dimensional electron gas (2DEG) detected by using second harmonic generation (SHG) imaging technique. The spin polarized electrons in the 2DEG are pumped by a single linear polarized laser beam and probed by another beam which produces reflective SHG. By comparing the images of SHG probed with left- and right-circular polarized laser beams, the spatial distributions of the effective charge and spin polarizations in the 2DEG sample are mapped out.

Polar Second-Harmonic Imaging to Resolve Pure and Mixed Crystal Phases along GaAs Nanowires

“…The SHG is sensitive to crystallographic symmetry changes that makes the SHG polarimetry a very promising technique for studying crystal structure and orientation in different types of nonlinear materials. Polarization-dependent SHG is effectively used for investigations of the nonlinear optical properties and different crystal structure symmetries in III–V materials, such as GaAs, ,, InAs, and GaN . Previous studies demonstrate highly efficient SHG in different types of semiconductor NWs, such as ZnO, ZnTe, CdS, ZnS, GaAs, ,,, and GaP .…”