The spin of an electron in a self-assembled InAs/GaAs quantum dot molecule is optically prepared and measured through the trion triplet states. A longitudinal magnetic field is used to tune two of the trion states into resonance, forming a superposition state through asymmetric spin exchange. As a result, spin-flip Raman transitions can be used for optical spin initialization, while separate trion states enable cycling transitions for non-destructive measurement. With two-laser transmission spectroscopy we demonstrate both operations simultaneously, something not previously accomplished in a single quantum dot.
@article{arxiv.0809.1673,
title = {Optical Spin Initialization and Non-Destructive Measurement in a Quantum Dot Molecule},
author = {Danny Kim and Sophia E. Economou and Stefan C. Badescu and Michael Scheibner and Allan S. Bracker and Mark Bashkansky and Thomas L. Reinecke and Daniel Gammon},
journal= {arXiv preprint arXiv:0809.1673},
year = {2009}
}