Two-dimensional optical control of electron spin orientation by linearly polarized light in InGaAs

TL;DR

This paper demonstrates that linearly polarized light can efficiently generate and control electron spin orientation in InGaAs, with spin directions tunable by polarization angle and independent of crystal axes.

Contribution

It reveals a novel extrinsic mechanism for electron spin generation using linearly polarized light in InGaAs, expanding beyond traditional circular polarization methods.

Findings

High-efficiency spin generation with linearly polarized light

Spin orientation can be controlled by polarization direction

Spin directions are independent of crystal axes

Abstract

Optical absorption of circularly polarized light is well known to yield an electron spin polarization in direct band gap semiconductors. We demonstrate that electron spins can even be generated with high efficiency by absorption of linearly polarized light in InGaAs. By changing the incident linear polarization direction we can selectively excite spins both in polar and transverse directions. These directions can be identified by the phase during spin precession using time-resolved Faraday rotation. We show that the spin orientations do not depend on the crystal axes suggesting an extrinsic excitation mechanism.