Stimulated emission and absorption of photons in magnetic point contacts: toward metal-based spin-lasers

TL;DR

This paper demonstrates that point contacts between ferromagnetic SmCo5 and copper can achieve spin-population inversion, leading to stimulated photon emission and absorption, which are fundamental steps toward developing metal-based spin-lasers.

Contribution

It introduces a novel experimental setup showing stimulated spin-flip photon emission and absorption in metallic point contacts, advancing the understanding of spin-laser mechanisms.

Findings

Resonant spin-flip photon emission observed as resistance peaks.

Photon absorption detected as resistance minima.

Potential for designing metallic spin-based lasers.

Abstract

Point contacts between high anisotropy ferromagnetic SmCo5 and normal metal Cu are used to achieve a strong spin-population inversion in the contact core. Subjected to microwave irradiation in resonance with the Zeeman splitting in Cu, the inverted spin-population relaxes through stimulated spin-flip photon emission, detected as peaks in the point contact resistance. Resonant spin-flip photon absorption is detected as resistance minima, corresponding to sourcing the photon field energy into the electrical circuit. These results demonstrate fundamental mechanisms that are potentially useful for designing metallic spin-based lasers.