相关论文: Electrical control of the exciton-biexciton splitt…
We show that two initially non-resonant quantum dots may be brought into resonance by the application of a single detuned laser. This allows for control of the inter-dot interactions and the generation of highly entangled excitonic states…
We perform high-resolution photocurrent (PC) spectroscopy to investigate resonantly the neutral exciton ground-state (X0) in a single InAs/GaAs self-assembled quantum dot (QD) embedded in the intrinsic region of an n-i-Schottky photodiode…
By the application of an in-plane magnetic field, we demonstrate control of the fine structure polarisation splitting of the exciton emission lines in individual InAs quantum dots. The selection of quantum dots with certain barrier…
Confining particles to distances below their de Broglie wavelength discretizes their motional state. This fundamental effect is observed in many physical systems, ranging from electrons confined in atoms or quantum dots to ultracold atoms…
The neutral biexciton cascade of single quantum dots is a promising source of entangled photon pairs. The character of the entangled state is determined by the energy difference between the excitonic eigenstates known as fine-structure…
We demonstrate control by applied electric field of the charge states in single self-assembled InP quantum dots placed in GaInP Schottky structures grown by metalorganic vapor phase epitaxy. This has been enabled by growth optimization…
The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole…
We investigate the effect of uniaxial stress on InGaAs quantum dots in a charge tunable device. Using Coulomb blockade and photoluminescence, we observe that significant tuning of single particle energies (~ -0.5 meV/MPa) leads to variable…
We demonstrate that the exciton and biexciton emission energies as well as exciton fine structure splitting (FSS) in single (In,Ga)As/GaAs quantum dots (QDs) can be efficiently tuned using hydrostatic pressure in situ in an optical cryostat…
Two-photon resonant excitation of the biexciton-exciton cascade in a quantum dot generates highly polarization-entangled photon pairs in a near-deterministic way. However, the ultimate level of achievable entanglement is still debated.…
We investigate the effect of Cooper pair injection in shifting biexciton energy level of low-symmetry (C2v) quantum dots (QDs) exhibiting nontrivial fine structure splitting. Coupling QDs to the superconducting coherent state forms extra…
Combining the capabilities of gate defined quantum transport devices in GaAs-based heterostructures and of optically addressed self-assembled quantum dots could open broad perspectives for new devices and functionalities. For example,…
We demonstrate optical control of the polarization eigenstates of a neutral quantum dot exciton without any external fields. By varying the excitation power of a circularly polarized laser in micro-photoluminescence experiments on…
In a charge tunable device, we investigate the fine structure splitting of neutral excitons in single long-wavelength (1.1\mu m < \lambda < 1.3 \mu m) InGaAs quantum dots as a function of external uniaxial strain. Nominal fine structure…
Employing the ultrafast control of electronic states of a semiconductor quantum dot in a cavity, we introduce a novel approach to achieve on-demand emission of single photons with almost perfect indistinguishability and photon pairs with…
We present a formal theory of single quantum-dot coupling to a planar photonic crystal that supports quasi-degenerate cavity modes, and use this theory to describe, and optimize, entangled-photon-pair generation via the biexciton-exciton…
We study biexcitonic states in two tunnel-coupled semiconductor quantum dots and show that such systems provide the possibility to produce polarization- entangled photons or spin-entangled electrons that are spatially separated at…
Photon indistinguishability, entanglement, and antibunching are key ingredients in quantum optics and photonics. Decay cascades in quantum emitters offer a simple method to create entangled photon-pairs with negligible multi-pair generation…
We compare the asymmetry-induced exchange splitting delta_1 of the bright-exciton ground-state doublet in self-assembled (In,Ga)As/GaAs quantum dots, determined by Faraday rotation, with its homogeneous linewidth gamma, obtained from the…
Single strain-induced quantum dots are isolated for optical experiments by selective removal of the inducing InP islands from the sample surface. Unpolarized emission of single, bi- and triexciton transitions are identified by…