Optical detection of single electron spin resonance in a quantum dot

TL;DR

This paper reports the optical detection of single electron spin resonance in a quantum dot, demonstrating sensitive control and observation of spin states using resonant optical pumping and rf magnetic fields.

Contribution

It introduces a novel optical detection scheme for single electron spins in quantum dots, revealing detailed spin dynamics and non-Markovian effects.

Findings

Sensitive detection of rf fields as low as a few micro-T

Observation of narrow spin resonances with 0.34 MHz linewidth

Evidence of non-Markovian dynamic processes in spin behavior

Abstract

We demonstrate optically detected spin resonance of a single electron confined to a self-assembled quantum dot. The dot is rendered dark by resonant optical pumping of the spin with a coherent laser. Contrast is restored by applying a radio frequency (rf) magnetic field at the spin resonance. The scheme is sensitive even to rf fields of just a few micro-T. In one case, the spin resonance behaves exactly as a driven 3-level quantum system (a lambda-system) with weak damping. In another, the dot exhibits remarkably strong (67% signal recovery) and narrow (0.34 MHz) spin resonances with fluctuating resonant positions, evidence of unusual dynamic processes of non-Markovian character.