title: Optical amplification using raman transitions between spin-singlet and spin-triplet states of a pair of coupled in-GaAs quantum dots.
abstract: We report the observation of steady-state optical amplification in Raman transitions between the lowest-energy spin states of a single quantum-dot molecule. Absorption and resonance fluorescence experiments demonstrate that the entangled two-electron singlet and triplet states have electric-dipole coupling to a common optically excited state. Fast spin relaxation ensures optical gain on the triplet transition when the singlet transition is driven resonantly. By embedding the quantum-dot molecule in a cavity of modest quality factor, a solid-state single-emitter laser can be realized.
authors.affiliation: Institute of Quantum Electronics, ETH Zurich, Switzerland.
authors.forename: J M
authors.initials: JM
authors.lastname: Elzerman
authors.forename: K M
authors.initials: KM
authors.lastname: Weiss
authors.forename: J
authors.initials: J
authors.lastname: Miguel-Sanchez
authors.forename: A
authors.initials: A
authors.lastname: Imamoglu