Excited State Quantum Couplings and Optical Switching of an Artificial Molecule

Abstract

We optically probe the spectrum of ground and excited state transitions of an individual, electrically tunable self-assembled quantum dot molecule. Photocurrent absorption measurements show that the spatially direct neutral exciton transitions in the upper and lower dots are energetically separated by only ~2 meV. Excited state transitions ~8-16 meV to higher energy exhibit pronounced anticrossings as the electric field is tuned due to the formation of hybridized electron states. We show that the observed excited state transitions occur between these hybridized electronic states and different hole states in the upper dot. By simultaneously pumping two different excited states with two laser fields we demonstrate a strong (88% on-off contrast) laser induced switching of the optical response. The results represent an electrically tunable, discrete coupled quantum system with a conditional optical response.

References in corpus (8)

• Direct Observation of Controlled Coupling in an Individual Quantum Dot Molecule
• Ultrafast optical control of entanglement between two quantum dot spins
• Ultrafast optical rotations of electron spins in quantum dots
• Engineering electron and hole tunneling with asymmetric InAs quantum dot molecules
• Optical Trapping of an Ion
• Optically Probing Spin and Charge Interactions in an Tunable Artificial Molecule
• Photoluminescence Spectroscopy of the Molecular Biexciton in Vertically Stacked Quantum Dot Pairs
• Direct observation of acoustic phonon mediated relaxation between coupled exciton states in a single quantum dot molecule

Cited by in corpus (9)

• Electrical control of inter-dot electron tunneling in a quantum dot molecule
• High fidelity optical preparation and coherent Larmor precession of a single hole in an InGaAs quantum dot molecule
• Electron states in a double quantum dot with broken axial symmetry
• All optical quantum control of a spin-quantum state and ultrafast transduction into an electric current
• Coulomb mediated hybridization of excitons in artificial molecules
• Excitons in quantum dot molecules: Coulomb coupling, spin-orbit effects and phonon-induced line broadening
• Using quantum state protection via dissipation in a quantum-dot molecule to solve the Deutsch problem
• Enhanced photocurrent readout for a quantum dot qubit by bias modulation
• Optical signatures of spin dependent coupling in semimagnetic quantum dot molecules