Resonant spin amplification in Faraday geometry

TL;DR

This paper demonstrates the realization of resonant spin amplification in Faraday geometry within quantum dots, revealing new insights into spin interactions and providing a tool to measure the g factor of charge carriers.

Contribution

It shows that RSA can occur in Faraday geometry for a central spin interacting with a fluctuating environment, which was previously unexpected.

Findings

RSA observed in Faraday geometry for quantum dots

High repetition rate pump pulses enhance RSA detection

RSA can be used to measure the longitudinal g factor

Abstract

We demonstrate the realization of the resonant spin amplification (RSA) effect in Faraday geometry where a magnetic field is applied parallel to the optically induced spin polarization so that no RSA is expected. However, model considerations predict that it can be realized for a central spin interacting with a fluctuating spin environment. As a demonstrator, we choose an ensemble of singly-charged (In,Ga)As/GaAs quantum dots, where the resident electron spins interact with the surrounding nuclear spins. The observation of RSA in Faraday geometry requires intense pump pulses with a high repetition rate and can be enhanced by means of the spin-inertia effect. Potentially, it provides the most direct and reliable tool to measure the longitudinal $g$ factor of the charge carriers.