Toward high-frequency operation of spin lasers

TL;DR

This paper develops a microscopic model for spin lasers, demonstrating that strain-induced birefringence can enable polarization oscillations exceeding 200 GHz, promising advancements in optical communication.

Contribution

It introduces a detailed spin-dependent optical gain model and shows how strain can enhance birefringence to achieve ultra-high-frequency polarization oscillations in spin lasers.

Findings

Strain induces large birefringence in spin lasers.

Polarization oscillation frequencies can exceed 200 GHz.

Potential for high-speed optical communication applications.

Abstract

Injecting spin-polarized carriers into semiconductor lasers provides important opportunities to extend what is known about spintronic devices, as well as to overcome many limitations of conventional (spin-unpolarized) lasers. By developing a microscopic model of spin-dependent optical gain derived from an accurate electronic structure in a quantum well-based laser, we study how its operation properties can be modified by spin-polarized carriers, carrier density, and resonant cavity design. We reveal that by applying a uniaxial strain, it is possible to attain a large birefringence. While such birefringence is viewed as detrimental in conventional lasers, it could enable fast polarization oscillations of the emitted light in spin lasers which can be exploited for optical communication and high-performance interconnects. The resulting oscillation frequency ($>200$ GHz) would significantly exceed the frequency range possible in conventional lasers.