The phase of a single quantum state is undefined unless the history of its creation provides a reference point. Thus, quantum interference may seem hardly relevant for the design of deterministic single-electron sources which strive to isolate individual charge carriers quickly and completely. We provide a counterexample by analyzing the nonadiabatic separation of a localized quantum state from...

Introduction: Quantum dots are attractive quantum structures owing to their superior characteristics and broad applications. A semiconductor laser with a quantum dot active region has been proven to exhibit excellent characteristics, including high differential gain, high modulation bandwidth, low threshold currents, and temperature insensitive threshold current density [1]. Quantum dot vertica...

One of the main properties of few electron quantum dots is the supression of charge current when the energy cost of introducing an extra electron in the system is large due to the charge repulsion inside the quantum dot (QD). In such a case, the system presents Coulomb blockade, showing characteristic curves where current only flows for certain values of the chemical potentials[1]. Between thes...

For coherent electron spins, hyperfine coupling to nuclei in the host material can either be a dominant source of unwanted spin decoherence1–3 or, if controlled effectively, a resource enabling storage and retrieval of quantum information4–7. To investigate the effect of a controllable nuclear environment on the evolution of confined electron spins, we have fabricated and measured gate-defined ...

An optical pulse injection locking technique is employed to generate shorter pulses from a passively modelocked quantum dot laser. The optical pulse injection locking enables the coherent addition of phaselocked longitudinal mode groups from two separate modelocked lasers without the use of stabilisation control loops, thus increasing the spectral bandwidth output resulting in optical pulses wi...

Quantum Dots: Coulomb Blockade, Mesoscopic Fluctuations, and Qubit Decoherence The continuous minituarization of integrated circuits is going to affect the underlying physics of the future computers. This new physics first came into play as the effect of Coulomb blockade in electron transport through small conducting islands. Then, as the size of the island L continued to shrink further, the qu...

the electronic conductance at zero temperature through a quantum wire with side-connected asymmetric quantum ring (as a scatter system) is theoretically studied using the non-interacting hamiltonian anderson tunneling method. in this paper we concentrate on the configuration of the quantum dot rings. we show that the asymmetric structure of qd-scatter system strongly influences the amplitude an...

Monolithic passively mode-locked quantum dot lasers with excited-state transition were investigated in a broad operating range without ground-state lasing. Optical and electrical characteristics of these mode locked lasers were studied in detail at different levels of injection current and absorber bias. Very different behaviors in the evolution of the hysteresis, the optical spectra and the ev...

Low threshold and widely tunable InAs/GaAs quantum-dot lasers are implemented with grating-coupled external-cavity arrangement. Throughout the tuning range of 130 nm, from 1160 to 1290 nm, the threshold current density is not more than 0.9 kA/cm2 and no noticeable threshold jump is observed. For a shorter-cavity device, the injection current is kept at a record low value of 90 mA but the tuning...