The fast dephasing of electron spins in an ensemble quantum dots is detrimental for applications information processing. We show here that can be overcome by using a periodic train light pulses to synchronize the phases precessing spins, and we demonstrate this effect singly charged (In,Ga)As/GaAs dots. This mode locking leads constructive interference contributions Faraday rotation presents potential based on robust coherence within

By performing a full analysis of the projected local density states (LDOS) in photonic crystal waveguide, we show that phase plays crucial role symmetry light-matter interaction. considering quantum dot (QD) spin coupled to waveguide (PCW) mode, demonstrate interaction can be asymmetric, leading unidirectional emission and deterministic entangled photon source. Further understanding associated with both LDOS QD is essential for range devices realised PCW. We also how entanglement completely...

Electron spin coherence has been generated optically in $n$-type modulation doped $(\mathrm{In},\mathrm{Ga})\mathrm{As}/\mathrm{GaAs}$ quantum dots (QDs) which contain on average a single electron per dot. The arises from resonant excitation of the QDs by circularly polarized laser pulses, creating coherent superposition an and trion. Time dependent Faraday rotation is used to probe precession oriented electrons about transverse magnetic field. generation can be controlled pulse intensity,...

An in-plane spin-photon interface is essential for the integration of quantum dot spins with optical circuits. The dipole a lies in plane and spin optically accessed via circularly polarized selection rules. Hence, single waveguide, which can transport only one linear polarization component, cannot communicate state between two points on chip. To overcome this issue, we introduce based orthogonal waveguides, where emitted by mapped to path-encoded photon. We demonstrate operation deducing...

A photosynthetic algal intracellular organelle containing a living opal responds dynamically to environmental illumination.

The effects of excess electron occupation on the optical properties excitons (X) and biexcitons $(2X)$ in a single self-assembled InGaAs quantum dot are investigated. behavior X $2X$ differ strongly as number electrons is varied with biexciton being much more weakly perturbed result its filled s-shell ground state, direct manifestation shell-filling effects. Good correlation found between charging thresholds observed from recombination by p-shell occupation, observation recombination.

The authors investigate the multiple confined modes of GaAs L3 photonic crystal air-bridge cavities, using single layers InAs quantum dots as active internal light sources. Theoretical results for energies, quality factors, and emission polarizations first five are compared to experimental data cavities with lattice periods ranging from 240to270nm. also present in-plane field distributions each mode. In addition well-known factor improvement fundamental mode, they show that outward...

We probe the permanent excitonic dipole of neutral and positively charged excitons in individual ${\mathrm{In}}_{0.5}{\mathrm{Ga}}_{0.5}\mathrm{As}$ self-assembled quantum dots using Stark effect perturbation spectroscopy. A systematic reduction is found as excess holes are controllably added to containing a single exciton $({X}^{0})$. Calculations few-body states show that this arises from strong, Coulomb-mediated, spatial redistribution wave function upon charging. By investigating...

A key to ultralong electron spin memory in quantum dots (QDs) at zero magnetic field is the polarization of nuclei, such that stabilized along average nuclear field. We demonstrate spin-polarized electrons n-doped (In,Ga)As/GaAs QDs align via hyperfine interaction. feedback onto occurs, leading stabilization their due formation a polaron [I. A. Merkulov, Phys. Solid State 40, 930 (1998)]. Spin depolarization both systems consequently greatly reduced, and coupled electron-nuclear system...

We investigate the energy splitting, quality factor and polarization of fundamental modes coupled L3 photonic crystal cavities. Four different geometries are evaluated theoretically, before experimentally investigating coupling in a direction at 30◦ to line In this geometry, smooth variation splitting with cavity separation is predicted observed, together significant differences between polarizations bonding anti-bonding states. The controlled states potentially useful for applications that...

Semiconductor quantum dots in photonic crystal waveguides are building blocks for technology. Placing the at locations where waveguide modes have circular polarization enables light emission only one direction with a high probability of coupling to mode, beta factor. The authors use spectral imaging determine factor and directionality, doing away assumptions on rates into nonguided modes. In fast-light regime, they find coupling, close unity, quantum-dot position inside waveguide.

The generation of photon pairs in single quantum dots is based on a process that is, its nature, deterministic. However, an efficient extraction these from high-index semiconductor host material requires engineering the photonic environment. We report micropillar-based device featuring efficiency 69.4(10)$\%$ achieved by harnessing broadband operation suitable for emitted dot. Opposing approaches rely solely Purcell enhancement to realize efficiency, our solution exploits suppression...

Vision is the primary sensory modality of birds, and its importance evident in sophistication their visual systems. Coloured oil droplets cone photoreceptors represent an adaptation avian retina, acting as long-pass colour filters. However, we currently lack understanding how optical properties morphology component structures (e.g. droplet, mitochondrial ellipsoid outer segment) photoreceptor influence transmission light into segment ultimate effect they have on receptor sensitivity. In this...

We report the first experimental observation of an Excitonic Optical Tamm State supported at interface between a periodic multilayer dielectric structure and organic dye-doped polymer layer. The existence such states is enabled by metal-like optical properties excitonic layer based on aggregated dye molecules. Experimentally determined dispersion curves, together with simulated data, including field profiles, allow us to identify nature these new modes. Our results demonstrate potential...

Unidirectional (chiral) emission of light from a circular dipole emitter into waveguide is only possible at points perfect polarization (C points), with elliptical polarizations yielding lower directional contrast. However, there no need to restrict engineered systems dipoles, and an appropriate choice unidirectional for any polarization. Using rather than circular, typically increases the size area suitable chiral interactions (in exemplary mode by factor ∼30), while simultaneously...

We compare the asymmetry-induced exchange splitting ${\ensuremath{\delta}}_{1}$ of bright-exciton ground-state doublet in self-assembled $(\mathrm{In},\mathrm{Ga})\mathrm{As}∕\mathrm{GaAs}$ quantum dots, determined by Faraday rotation, with its homogeneous linewidth $\ensuremath{\gamma}$, obtained from radiative decay time-resolved photoluminescence. Postgrowth thermal annealing dot structures leads to a considerable increase linewidth, while strong reduction is simultaneously observed. The...

By application of external electric field, we demonstrate the ability to controllably manipulate homogenous linewidth exciton transitions in a single self-assembled In(Ga)As quantum dot (QD). Complementary emission (photoluminescence) and absorption (photocurrent) measurements are used probe directly competing processes radiative recombination carrier tunnelling escape from dot. At high fields $(\ensuremath{\gtrsim}100 \mathrm{k}\mathrm{V}/\mathrm{c}\mathrm{m})$ line shape is lifetime...

Continuum transitions in the absorption spectra of self-assembled InGaAs quantum dots are demonstrated to have an intrinsic origin, and arise from between wetting layer well dot confined states, agreement with recent theory predictions. The shown fall into two distinct groups, below 50 meV corresponding sharp line expected ideal atom picture, above where coupling discrete continuum is demonstrated. Electric-field-controlled resonant LO phonons also

We study the linear polarization of emission from single quantum dots embedded in an "L3" defect nanocavity a two-dimensional photonic crystal. By using narrow linewidth optical excitation resonance with higher-order modes, we are able to achieve strong dot intensity whilst reducing background surrounding lattice. find that all observed emit very strongly linearly polarized light same orientation as closest mode, despite fact these may be spectrally detuned by several times mode linewidth....

Using the helicity of a non-resonant excitation laser, control over emission direction an InAs/GaAs quantum dot is demonstrated. The located off-center in crossed-waveguide structure, such that photons opposite circular polarization are emitted into waveguide directions. By preferentially exciting spin-polarized excitons, can therefore be controlled. directional quantified by using ratio intensity light coupled two waveguides, which reaches maximum ±35%.

We present evidence of optical Tamm states to surface plasmon polariton (SPP) coupling. experimentally demonstrate that for a Bragg stack with thin metal layer on the surface, hybrid Tamm-SPP modes may be excited when grating air-metal interface is introduced. Out-coupling via free space propagation shown enhance transmission as well directionality and polarization selection transmitted beam. suggest this system will useful those devices, where metallic electrical contact beaming control needed.

We report on the coherent optical response from an ensemble of (In,Ga)As quantum dots (QDs) embedded in a planar Tamm-plasmon microcavity with quality factor approx. 100. Significant enhancement light-matter interaction is demonstrated under selective laser excitation those which are resonance cavity mode. The manifested through Rabi oscillations photon echo, demonstrating control excitons picosecond pulses at intensity levels more than order magnitude smaller as compared bare dots. decay...

It is shown that cavities formed between a multilayer quarter-wave Bragg reflector and metal mirror which support Tamm plasmons can be modelled by using hard-mirror approximation including appropriate penetration depths into the mirrors. Results from this model are in excellent agreement with those found numerical methods. In addition modes laterally confined presence of metallic disc deposited on described effective index commonly used for vertical-cavity surface-emitting lasers (VCSELs)....