three different nanostructured semiconductor lasers were studied – the quantum dot passively mode-locked laser, the dual-mode quantum dot laser and the optically-injected quantum dot distributed feedback laser. The key milestones achieved were: 1) the use of optical feedback to reduce the timing jitter of the pulsed lasers from 295 fs/cycle to 32 fs/cycle, 2) experimental determination of the o...

We use the spin-polarized excitons in a single quantum dot to design optical controls for basic operations in quantum computing. We examine the ultrafast nonlinear optical processes required and use the coherent nonlinear optical responses to deduce if such processes are physically reasonable. The importance and construction of an entangled state of polarized exciton states in a single quantum ...

Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum do...

We demonstrate the first electrically pumped quantum-dot micro-ring lasers epitaxially grown on (001) silicon. Continuous-wave lasing around 1.3 μm was achieved with ultra-low thresholds as small as 0.6 mA and maximum operation temperatures up to 100°C. OCIS codes: (230.5590) Quantum-well, -wire and -dot devices; (140.5960) Semiconductor lasers; (140.3948) Microcavity devices; (160.3130) Integr...

We experimentally study the response of an injection-locked quantum dot semiconductor laser in the excitable regime to perturbations from an external, incoherent laser. We show that excitable pulses may be triggered both for perturbation wavelengths close to that of the quantum dot device and wavelengths detuned even by a few tens of nanometers.

We investigate sequential tunneling transport through a semiconductor double quantum dot structure by combining a simple microscopic quantum confinement model with a Mott-Hubbard type correlation model. We calculate nonperturbatively the evolution of the Coulomb blockade oscillations as a function of the interdot barrier conductance, obtaining good qualitative agreement with the experimental da...

The coherent generation of light, from masers to lasers, relies upon the specific structure of the individual emitters that lead to gain. Devices operating as lasers in the few-emitter limit provide opportunities for understanding quantum coherent phenomena, from terahertz sources to quantum communication. Here we demonstrate a maser that is driven by single-electron tunneling events. Semicondu...

Colloidal semiconductor quantum dots are promising for single-molecule biological imaging due to their outstanding brightness and photostability. As a proof of concept for single-molecule fluorescence resonance energy transfer (FRET) applications, we measured FRET between a single quantum dot and a single organic fluorophore Cy5. DNA Holliday junction dynamics measured with the quantum dot/Cy5 ...

The time evolution of the quantum entropy in a coherently driven threelevel quantum dot (QD) molecule is investigated. The entanglement of quantum dot molecule and its spontaneous emission field is coherently controlled by the gat voltage and the intensity of applied field. It is shown that the degree of entanglement between a three-level quantum dot molecule and its spontaneous emission fields...

Semiconductor self-assembled quantum dots form a three dimensional confinement for charge carriers in the solid state matrix. The confinement modifies the density of states, leading to atom like optical properties of quantum dots that can be studied by absorption or emission of photons. Due to the sharp resonance lines that are observed in optical spectra, quantum dots are often referred to as ...