Carbon quantum dots (CQDs) serve as a new class of ‘zero dimensional’ nanomaterial’s in thecarbon class with sizes below 10 nm. As light emitting nanocrystals, QDs are assembled from semiconductormaterials, from the elements in the periodic groups of II-VI, III-V or IV-VI, mainly thanks to impacts of quantum confinement QDs have unique optical properties such as brighter, highly pho...

The ability to initialize excitonic states in the high-energy orbital levels of quantum dots provides additional degrees freedom for all-optical spin-driving protocols. Here, authors show that unconventional two-photon excitation can simultaneously photocreate two electron-hole pairs located on distinct a GaAs dot. Tuning laser energy allows triplet and singlet spin biexciton be selectively add...

We develop a theoretical formalism to model the linear spectrum of a quantum dot embedded in a highquality cavity, in the presence of an arbitrary mechanism modifying the homogeneous spectrum of the quantum dot. Within the simple assumption of Lorentzian broadening, we show how the known predictions of cavity quantum electrodynamics are recovered. We then apply our model to the case where the q...

Optical spectra of a self-organized quantum dot with a single magnetic impurity are studied. The quantum dot potential and exchange interactions result in an additional fine structure of an exciton localized in a quantum dot with a magnetic impurity. In contrast to the undoped quantum dots, the ground state excitons in the quantum dot with a magnetic impurity are bright. It is also shown that a...

We present here a novel design to form an artificial quantum dot with electrical confinement and apply it to a Quantum Cascade Laser structure to realize a Quantum Dot Cascade Laser. A two-dimensional finite element method has been used to numerically simulate the novel design of electrical formation of an artificial quantum dot. The size of the quantum dot is electrically tunable and can be ap...

The excited states of neutral and charged single InGaAs/GaAs quantum dots are studied using a confocal microspectroscopy technique. Because of their different Coulomb energy shifts, the charged and neutral states of the same quantum dot can be selectively excited. The charge of the quantum dot is controlled by a photo-depletion mechanism. Time-resolved coherent spectroscopy shows that the depha...

Wilson’s Numerical Renormalization Group (NRG) is so far the only nonperturbative technique that can reliably access low–energy properties of quantum impurity systems. We present a recent extension of the method, the DM–NRG, which yields highly accurate results for dynamical quantities at arbitrary frequencies and temperatures. As an application, we determine the spectrum of a quantum dot in an...