Time domain optical manipulation of exciton and nuclear spin in a single self-assembled quantum dot

TL;DR

This paper demonstrates experimental control over exciton and nuclear spins in a single quantum dot using time domain optical techniques, showing coherent spin manipulation via continuum states.

Contribution

It introduces a novel method for coherent manipulation of electron and nuclear spins in a single quantum dot through optical pulse timing.

Findings

Clear observation of exciton and nuclear spin oscillations.

Controlled switching of emission polarization via pulse delay.

Evidence of coherent creation of exciton pairs with opposite spins.

Abstract

We have demonstrated experimentally the manipulation of exciton and nuclear spins in a single self-assembled In$_{0.75}$Al$_{0.25}$As/Al$_{0.3}$Ga$_{0.7}$As quantum dot. The oscillation of exciton and nuclear spin polarizations were clearly observed. The switching of the emissions in Zeeman split pair indicates that the exciton pair with opposite spins was created coherently via the continuum states and that we can control the electron and nuclear spin polarizations only by changing the delay time of the cross-linearly-polarized pulses. These suggest the high potentiality of electron and nuclear spin manipulation in a single QD via the continuum state.