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Illustrates that a combination of low-temperature photoluminescence (PL) and luminescence excitation (PLE) spectroscopies together with appropriate modelization can provide the information needed for control of diffusion in quantum well structures. Sample used in the study; Data on the PL and PLE spectra of the sample.

We evaluate the potential of confined Tamm plasmon structures for single photon extraction. A single quantum dot is inserted in a structure consisting of a gold microdisk deposited on a distributed Bragg reflector. The quantum dot exciton line experiences acceleration of spontaneous emission while the biexciton line experiences inhibition. This property leads to non-linearities in the emission dynamics and the photon statistics as a function of the excitation rate. We show that the device operates as a single photon source with a measured brightness of 0.20 ± 0.02 collected photons per pulse. By modeling the extraction efficiency, we show that efficiencies around 60% can be reached in optimized structures. [ABSTRACT FROM AUTHOR]

This article reports on the properties of ultraviolet nanoimprint lithography dedicated imprinting materials. Studied solutions are composed of a diacrylate-based monomer and a variable amount (1%, 2%, and 4% in weight) of three different photoinitiators from Ciba Specialty Chemicals (Irgacure 819, Irgacure OXE02, and Irgacure 379). Photopolymerization kinetic studies were conducted on these solutions. Quantity and type of photoinitiator could be optimized in order to obtain a polymerization rate higher than 95% with an exposure dose as low as 20 mJ/cm2. The etch resistance of this home-developed imprinting resist was characterized under standard plasma etching conditions. We observed that the polymerization rate has a large influence on the plasma etch resistance, and we show that the etch rates of our best material is comparable to the one measured for 193 nm photolithography resists and makes it a very good candidate as a masking layer for direct pattern transfer. [ABSTRACT FROM AUTHOR]

Using an advanced tight-binding approach, we estimate the anisotropy of the tunnel transmission associated with the rotation of the 5/2 spin of a single Mn atom forming an acceptor state in GaAs and located near an AlGaAs tunnel barrier. Significant anisotropies in both in-plane and out-of-plane geometries are found, resulting from the combination of the large spin-orbit coupling associated with the p-d exchange interaction, cubic anisotropy of heavy-hole dispersion and the low C2v symmetry of the chemical bonds. [ABSTRACT FROM AUTHOR]

We report on an experimental and numerical study of the spatial and spectral properties of the optical modes in coupled pillar microcavities. Highly efficient photon blockade or bright sources of entangled photon pairs can be implemented by coupling a single quantum emitter to coupled cavities. Parameters for optimal coupling with a single quantum emitter are identified. Polarization properties, which are critical for both applications, are finally discussed. We show that an extremely small polarization splitting is obtained for the first modes in a wide range of parameters. [ABSTRACT FROM AUTHOR]

The exciton and biexciton lines of a single quantum dot are deterministically coupled to the optical modes of a photonic molecule. The resonance between the quantum dot emission lines and the molecule cavity modes is reached at 53 K. The device operates as a very bright source of entangled photon pairs, with an extraction efficiency of 40% for each photon of the pair. Our measurements show that the use of Purcell effect allows to quench the exciton spin relaxation during the radiative cascade, at 53 K and at high excitation power. [ABSTRACT FROM AUTHOR]

Crystal phase heterostructures, consisting of homogeneous composition zinc-blende inclusions in wurtzite InP and GaAs nanowires are investigated theoretically in the frame of the extended-basis tight-binding approach. Increased band gap for the wurtzite phase and staggered type II band alignment are predicted for both materials. Comparison of theoretical results with microphotoluminescence measurements on single InP nanowires yields fair semiquantitative agreement. [ABSTRACT FROM AUTHOR]

Using low temperature in situ optical lithography, we fabricate pillar microcavities with quality factors around 2×104. Each pillar embeds a spatially and spectrally resonant single InGaAs quantum dot (QD). Light-matter strong coupling regime is reached for 100% of the fabricated pillars for which the resonance can be tuned through temperature. This is a demonstration of scalable and deterministic implementation of strongly coupled cavity-QD devices. [ABSTRACT FROM AUTHOR]

We use optical orientation technique to monitor the degeneracy control of exciton states in a single InAs/GaAs quantum dot, achieved by applying an in-plane electric field. Under circularly polarized quasiresonant excitation, the exciton photoluminescence shows a pronounced maximum of circular polarization at electric field corresponding to zero fine structure splitting. By analyzing the width of this maximum we are able to determine the homogeneous linewidth of the excitonic transition. This experimental method is shown to be very efficient to test and possibly tune the photonic properties of an individual quantum dot for the emission of entangled photon pairs. [ABSTRACT FROM AUTHOR]

The far field radiation pattern of microdisk cavities embedding a quantum well is measured through angle resolved microphotoluminescence. The radiation pattern presents two narrow lobes slightly off the disk plane, in apparent contradiction with previous theoretical predictions. The observed radiation pattern is shown to result from interferences with light reflected by the sample substrate. It can be fully reproduced given the microdisk precise geometry as well as the whispering gallery mode azimuthal number. [ABSTRACT FROM AUTHOR]

The authors report a study of the linear electro-optic coefficient in waveguides containing InGaAs/GaAs quantum dots with a band gap at 1.3 μm. The Pockels effect is investigated in the 1.55 μm telecommunication window. The measured linear electro-optic coefficient for InGaAs/GaAs is ∼3.4×10-11 m/V, much higher than that of the bulk or quantum well material. An ∼35% enhancement of the phase variation is achieved compared to that obtained in bulk GaAs waveguides. Finally, a spectral bandwidth of ∼100 nm is demonstrated in the 1.5–1.6 μm window. [ABSTRACT FROM AUTHOR]

The influence of an in-plane electric field on the optical properties of single quantum dots is investigated. On a sample containing a plane of InAs/GaAs dots, micrometer-size electro-optical structures were produced in order to apply an external electric field in the dot plane. A large decrease of the anisotropic exchange splitting, correlated with the in-plane Stark shift, is observed. [ABSTRACT FROM AUTHOR]

Reports on the observation of anisotropy of the propagation index with respect to propagation direction in planar waveguides containing quantum wells. In-plane polarization anisotropy of the absorption observed for light propagating along the growth axis.

We describe photoluminescence investigations in InAs-GaAs superlattices in the thin layer limit (10–20 Å). The data, which are compared to theoretical results obtained from band structure calculations, yield an estimate of the conduction-band discontinuity of 550 meV at the interfaces. They also show that although the superlattice has a band gap (765 meV) close in energy to that of the corresponding bulk InxGa1-xAs alloy (800 meV), the band structures are very different. In the superlattice, electrons and light holes appear to be the important carriers, and they tend to be spatially separated, to the extent that this is meaningful in the thin layer limit. [ABSTRACT FROM AUTHOR]

We observe that the energy of the GaSb longitudinal optical phonons in GaSb-AlSb superlattices is about 2 cm-1 lower than in bulk GaSb. We show that this effect is fully explained by the consideration of the misfit strains which are known to exist in these superlattices. This shift of the Raman frequency allows a direct optical determination of the strains in heterostructures. [ABSTRACT FROM AUTHOR]

Examines a laser emission at low temperature from an optically pumped InP-AlInAs superlattice grown by chemical vapor deposition. Measurements of low level photoluminescence excitation; Occurrence of laser emission; Localization of separated conduction and valence level; Exhibition of high radiative efficiency.

The modulation by an external electric field of the resonant tunneling coupling between adjacent wells in a thin layer superlattice results in a blue shift of the effective absorption edge. We present a study of the electroabsorption in Al0.24Ga0.24In0.52As-Ga0.47 In0.53 As superlattices, which evidence directly this remarkable effect, and we discuss its application to the design of new electro-optical modulators. [ABSTRACT FROM AUTHOR]

We report the observation in InAs-GaSb semiconductor superlattices of a photovoltaic effect that has a quantum origin, as it arises from the spatial separation of the electron and hole ground-state wave functions in these type II superlattices. The results are consistent with the simplest theoretical predictions, except for the voltage sign, which evidences a depopulation of the surface layer. [ABSTRACT FROM AUTHOR]

Observes optical transmission bistability in InGaAs-AlInAs superlattices. Suitability of bistable devices for parallel information processing; Functions of electro-optical bistables at low power; Use of built-in electric field.

We discuss optical data obtained on (InAs/GaAs)-InGaAlAs multiquantum well structures grown by molecular beam epitaxy. The combined use of photoluminescence and photoluminescence excitation to study such structures is an efficient test of the quality of the highly strained InAs/GaAs ordered alloy, which is used as the well material. The electron effective mass and the lifting of the valence-band degeneracy in InAs/GaAs short-period superlattices are obtained experimentally for the first time. [ABSTRACT FROM AUTHOR]

We report the first room-temperature observation of Wannier–Stark localization under waveguide configuration in a short-period InGaAs-InAlAs superlattice. Using the ‘‘oblique’’ transition connecting a hole localized in a well with an electron localized in the adjacent well we have achieved a modulator having a 20 dB extinction ratio and a 3 dB attenuation with a drive voltage as low as 0.8 V. Our device is a 560-μm-long waveguide operating at 1.55 μm under TE polarization mode. [ABSTRACT FROM AUTHOR]