Spin fine structure of optically excited quantum dot molecules

Tunneling effects on fine-structure splitting in quantum-dot molecules.

We theoretically study the effects of bias-controlled interdot tunneling in vertically coupled quantum dots on the emission properties of spin excitons in various bias-controlled tunneling regimes. As a main result, we predict substantial reduction of optical fine-structure splitting without any drop in the optical oscillator strength for the coupled dots with high tunneling rates. This special...

Optically probing the fine structure of a single Mn atom in an InAs quantum dot.

We report on the optical spectroscopy of a single InAs/GaAs quantum dot doped with a single Mn atom in a longitudinal magnetic field of a few Tesla. Our findings show that the Mn impurity is a neutral acceptor state A0 whose effective spin J=1 is significantly perturbed by the quantum dot potential and its associated strain field. The spin interaction with photocarriers injected in the quantum ...

Fine structure in the excitonic emission of InAs/GaAs quantum dot molecules

The exciton fine structure in self-assembled coupled quantum dots with barriers of varying widths is studied in detail. For narrow barriers we find doublet splittings of the molecule ground state exciton in magnetic field, while for wide barriers in some cases a multiplet of emission lines is observed. Pronounced anticrossings occur in the field dispersion of such a multiplet with details depen...

Optically injected quantum-dot lasers.

The response of an optically injected quantum-dot semiconductor laser (SL) is studied both experimentally and theoretically. In particular, the nature of the locking boundaries is investigated, revealing features more commonly associated with Class A lasers rather than conventional Class B SLs. Experimentally, two features stand out; the first is an absence of instabilities resulting from relax...

High-fidelity initialization of long-lived quantum dot hole spin qubits by reduced fine-structure splitting