This PDF file contains the front matter associated with SPIE Proceedings Volume 8271, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Silver doped sodium borate glass was made by the melt quenching technique. As made glass, did not reveal any absorption transitions in the visible or ultraviolet region. Differential scanning calorimeter was used to measure glass transition temperature. Heat treated glass revealed absorption peak at 410 nm due to surface plasmon resonance. Under violet laser excitation the glass revealed emission at 450 - 620 nm, whose lifetimes are more than 30μs. Under near resonant excitation it revealed intense Raman scattering. We also made multielement oxide glasses co-doped with silver and Er³⁺ and performed spectroscopic studies. Energy upconversion was observed from Er³⁺ at 415 nm in a 2% Ag co-doped oxide glass but not in other glasses. Infrared to visible upconversion studies were performed in all these glasses under near-infrared laser excitation. 2% Ag doped glass exhibited enhanced upconversion signals from erbium than that of other glasses.

In this work, the physical and optical properties of gold nanoparticles functionalized with laterally grafted nematic ligands were studied. In particular, the influence of the nanoparticle size on the mesomorphic behavior and optical properties of the composite was investigated. To obtain an in-plane alignment of the mesogens, thin oriented films were prepared by shearing and characterized by polarized absorption spectroscopy. While the sub-2nm nanoparticle thin film only showed birefringence due to a strong damping of the plasmon resonance, larger NPs exhibit a strong dichroism with a shift of the NP plasmon resonance by about 50 nm. These results demonstrate the possibility to obtain a bulk NP metamaterial with tunable plasmonic properties by chemical engineering of the NP ligands.

Structural, optical and electrical studies of several hybrids of organic and inorganic nanostructures as well as core shell nanocrystalline structures will be presented. The effects of thermal annealing on the morphological and photoconductive properties of cadmium selenide quantum dots coreshell quantum dots together with indicate that there are collective events happening due to annealing. Two different types of hybrid structures will be discussed. Optical and electrical experimental results in semiconductor nanostructures in conductive polymers as well as those that were integrated into the organic photosystem I (PS1), as part of an artificial light harvesting complex (LHC) will be presented.

The transport and thermal properties of HgTe colloidal quantum dot films with cut-off wavelengths in the mid-IR are investigated. The cut-off wavelength of this material can be tuned over the 3-5 μm range, which makes it a promising alternative to existing high cost detectors. Post deposition processes such as ligand exchange and atomic layer deposition are investigated as a way to increase the carrier mobility.

The manuscript summarizes our current research on PbS quantum dots. The emission and transmission features in the temperature range of 5 K - 300 K of 4.7 nm PbS quantum dots were investigated and theoretically analyzed with the Fan model, which is based upon the phonon-electron interaction. The model - although designed for bulk semiconductors - apply for quantum dots with the potential to determine fundamental properties such as the Debye temperature.

Efficient sources of indistinguishable single photons are a key resource for various applications in fields like quantum sensing, quantum metrology and quantum information processing. In this contribution we report on single photon generation based on III-V semiconductor quantum dots (QDs). To increase the emission efficiency of single photons, it is essential to tailor the radiative properties of the quantum dot emitters by engineering their photonic environment. We present optimized single photon emitters being based on both micropillar and photonics crystal cavities, for applications in a vertical platform and on-chip in-plane platform, respectively. Electrically driven single photon sources with self assembled semiconductor QDs embedded into GaAs/AlAs micropillar cavities emit on demand net rates of ~35 MHz single photons, thus being well exploitable in quantum key distribution systems. In order to establish also a spatially deterministic fabrication platform, position controlled quantum dots are integrated into p-i-n micropillar cavities and single photon emission of a coupled QD-micropillar diode system is observed. Efficient broadband coupling of single photons into photonic crystal waveguides provides the basis for all on-chip quantum information processing, and an according approach is reported.

We demonstrate theoretically how photon-assisted dephasing by the electron-phonon interaction in a coupled cavity-quantum dot system can be significantly reduced for specific QD-cavity detunings. Our starting point is a recently published theory,¹ which considers longitudinal acoustic phonons, described by a non-Markovian model, interacting with a coupled quantum dot-cavity system. The reduction of phonon-induced dephasing is obtained by placing the cavity-quantum dot system inside an infinite slab, assuming spherical electronic wavefunctions. Based on our calculations, we expect this to have important implications in single-photon sources, allowing the indistinguishability of the photons to be improved.

We fabricated micro-spikes on the surface of silicon by using femtosecond laser pulses. By changing the fabrication condition, i.e., the power of laser, the number of laser pulses, the wavelength of laser, and the proportional relation between laser power and pulse number under the same laser fluence, we found many interesting phenomena, which proved there was a special relation between laser parameters and the surface morphology. All these results are important for the optimal fabrication of surface-microstructured photovoltaic material with high absorptance and good photoelectric properties, for the practical applications of solar cell, et al.

Recent innovations in Supercontinuum or white laser sources provide a very useful tool to probe nanomaterials physical and optical properties. Onera, The French Aerospace Lab, has developed a fast, in-line and comprehensive optical characterization method. From the combination of hyperspectral, polarized and angular measurements, physical properties of dense nanomaterials are to be retrieved. Based on achieved results, hyperspectral polarized scattering properties are discussed depending on microphysical properties. This technique is applied to a wide range of nanomaterials in suspensions: polymer, metal-oxide or metallic nanoparticles. It can be applied in various fields as chemical control, defence, atmospheric studies or aeronautical industry.

Droplet Epitaxy is a variant of molecular beam epitaxy for the fabrication of quantum nanostructures with highly designable shapes and complex morphologies. With Droplet Epitaxy it is possible to combine different quantum structures, namely quantum dots, quantum rings and quantum disks into a single unit, thus allowing an unprecedented control over electronic properties of the fabricated quantum nanostructures.

Multilayer quantum dots were grown using SSMBE. Seed layer of InAs QD was grown over 1000Å intrinsic GaAs layer on semi-insulating GaAs (001) substrate and capped with 30Å quaternary In_0.21Al_0.21Ga_0.58As and 90Å intrinsic GaAs layer for samples A and B while for sample C it was 20Å and 80Å. Growth rate was 0.2011 ML/s for samples A and C whereas 0.094 ML/s for sample B. Each sample was annealed at 650°C, 700°C, 750°C and 800°C. Greater growth-rate produced more strain in samples A and C producing more dot families and for sample B these increased with annealing because of the interdiffusion of constituents among the QDs. 750°C annealed samples A and C showed higher integrated PL intensity and activation energy because carriers found lower minimum energy states for relaxation, attributed to higher growth rate. In/Ga interdiffusion caused blue shift in photoluminescence(PL) spectra for samples B and C at higher annealing temperatures whereas due to greater capping layer thickness almost no shift for sample A due to intermixing of In-Al between the quaternary alloy and wetting layer, making it thermally stable. Decrease in FWHM due to enhanced carrier relaxation is counterbalanced by non-resonant multi-phonon assisted tunneling processes, suggesting good uniformity.

Vertically coupled multilayered InAs/GaAs QDs covered with thin InGaAs strain reducing layer (SRL) is interesting to address today's technological demand. We report low temperature photoluminescence (PL) investigations for such single and multilayered structures grown using MBE, where SRL thickness is varied. Use of SRL layer within structures is observed to be responsible for high activation energies (E_o) indicating the reduction of the electron phonon interaction in QDs. Deviation of experimental data with Varshni's model (E(T)=E_o-αT²/τ+β) suggests that InAs QDs have different properties than the bulk. Extracted theoretical values of E_o are observed to be much higher than that of bulk InAs, while the values of β ≥ 120 K which are close to InGaAs suggests the strong effect of misfit stress and the quantum confinement effects in the structures. Anomalous behavior of ground state (GS) peak linewidth observed especially for annealed multilayer structures indicates probable inter diffusion of In/Ga atoms between QDs and barrier layers. Blue shift of GS peak position with broadened linewidth with loss of intensity in case of samples annealed at 800 °C can be due to strain driven alloy decomposition as a result of adatom interdiffusion. Presence of SRL layer is observed to prevent the formation of the non radiative centers at high temperature annealing, which usually causes sharp decrease in E_a. This indicates the importance of such structures to be used in optoelectronic applications, where the structures are sandwiched between high temperatures grown InGaAs cladding layers.

We investigated the effect of the alloy composition of InGaAsP barrier layers on the photoluminescence (PL) properties of InAs columnar quantum dots (CQDs) grown by metal organic vapor phase epitaxy (MOVPE). The PL wavelength of the CQDs was controlled by the strain of the InGaAsP barrier layers for fixed bandgap wavelength conditions. The PL intensity of the CQDs showed significant increase with the bandgap energy of the barrier layers, that is, with increasing indium and phosphorus composition, due to the reduced defects and dislocation in the samples. The result is considered to be related to the miscibility of the InGaAsP quaternary alloy at a low growth temperature. By applying a larger bandgap energy to the barrier layers, triple-stacked CQDs with high crystalline quality was demonstrated in the 1.55-μm region.

We have investigated the temperature dependence of InAs columnar quantum dots (CQDs) surrounded by InGaAsP barriers with different bandgap energies toward high-temperature performance for semiconductor optical amplifiers. It was found that larger bandgap energy in InGaAsP side barriers enabled to increase the quasi-Fermi level (F) separation between the conduction and valence bands from theory. We have fabricated two types of CQD-SOAs with different side barrier energies and compared temperature characteristics. Decrease in the material gains for CQD with a larger side barrier bandgap was suppressed by 20% with increasing temperature from 25 °C to 85 °C.

Compensation for loss by introducing gain media in optical metamaterials was suggested by Ramakrishna and Pendry (Phys. Rev. B, 67, 201101, 2003). In this work, applying finite-difference-time-domain simulations, we analyzed an Au nanorod (AuNR) structure, as well as fishnet nanostructures with varying positioning of the gain medium. Transmittance, reflection and absorption spectra for an AuNR nanostructure incorporating InP quantum dots (QDs) and of a fishnet nanostructure incorporating InAs QDs have shown that despite limitations, results are encouraging in increasing the transmittance upon gain medium incorporation in the passive regime.