Sub-Wavelength Terahertz Spin-Flip Laser Based on a Magnetic Point-Contact Array

TL;DR

This paper introduces a novel sub-wavelength terahertz laser utilizing a nano-composite gain medium with metal/ferromagnetic point contacts, enabling single-mode operation through spin-flip stimulated emission at ultra-high current densities.

Contribution

The work presents a new design for a sub-wavelength THz disk laser based on a nano-composite gain medium with embedded metal/ferromagnetic point contacts, facilitating single-mode lasing.

Findings

Achieves single-mode operation in a sub-wavelength THz disk laser.

Utilizes spin-flip relaxation for stimulated emission.

Overcomes lasing thresholds with ultra-high current densities.

Abstract

We present a novel design for a single-mode, truly sub-wavelength THz disk laser based on a nano-composite gain medium comprising an array of metal/ferromagnetic point contacts embedded in a thin dielectric layer. Stimulated emission of light occurs in the point contacts as a result of spin-flip relaxation of spin-polarized electrons that are injected from the ferromagnetic side of the contacts. Ultra-high electrical current densities in the contacts and a dielectric material with a large refractive index, neither condition being achievable in conventional semiconductor media, allows the thresholds of lasing to be overcome for the lowest-order modes of the disk, hence making single-mode operation possible.