Recently, AlN bulk crystals with very high crystal quality have become available in diameters up to 25 mm. Metalorganic vapor phase epitaxy (MOVPE) allows to grow either very pure homoepitaxial AlN layers, or layers with controlled silicon (n-type) doping. We investigated such layers by low-temperature photoluminescence (PL), reflectance, and ellipsometry. We find very narrow lines, which allow...

We report on the implementation of an optical tweezer system for controlled transport of ultracold atoms along a narrow, static confinement channel. The tweezer system is based on high-efficiency acousto-optic deflectors and offers two-dimensional control over beam position. This opens up the possibility for tracking the transport channel when shuttling atomic clouds along it, forestalling atom...

Optical material properties have been studied in a wide wavelength range. The aim is future use of spectral design for camouflage. The main characterization techniques used in this work are Reflection Spectroscopy, Scatterometry (BRDF) and Mueller Matrix Ellipsometry. Six camouflage evaluation criteria based on reflection, emissivity, polarization, gloss, dynamic coloring and broad band propert...

Cu2ZnSnSe4 thin films were synthesised by selenisation of magnetron sputtered metal precursors. The band gap determined from the absorption spectra increases from 1.01 eV at 300 K to 1.05 eV at 4.2 K. In lower quality films photoluminescence spectra show a broad, low intensity asymmetric band associated with recombination of free electrons and holes localised on acceptors in the presence of spa...

The importance of microscopic morphological control to metal electroand electroless deposition in several emerging technologies is discussed. The use of in situ optical probes of the morphological development of deposits is described. A number of these are reviewed to describe both the potential of each method and the available literature on studies of electroand electroless deposition. Include...

Naphthobipyrrole-derived porphycenes are synthesized for the first time via McMurry coupling of the β-alkylated 2,9-diformylnaphthobipyrrole derivatives, which in turn were prepared easily from 2,3-naphthalene bishydrazine in four steps. Insertion of nickel into the porphycene core results in transformation of the rectangular N4-core into a square type geometry owing to the fusion of naphthalen...

Imaging approaches are an essential tool for following up over time representative parameters of in vivo models, providing useful information in pharmacological studies. Main advantages of optical imaging approaches compared to other imaging methods are their safety, straight-forward use and cost-effectiveness. A main drawback, however, is having to deal with the presence of high scattering and...

in this paper, based on the coupled-mode and carrier rate equations, a dynamic model and numerical analysis of a multi quantum well (mqw) chirped distributed feedback semiconductor optical amplifier (dfb-soa)  all-optical flip-flop is precisely derived. we have analyzed the effects of strains of qw and mqw and cross phase modulation (xpm) on the dynamic response, and rise and fall times of the ...

ZnO nanorod was prepared by microwave assisted method. The crystal structure of the nano powders were confirmed by X-Ray diffraction analysis and the mean particle size was estimated by the Scherrer,s formula .The surface morphology of the nano particles were analyzed by   using SEM . The absorption spectrum of the material in the UV-Vis range was recorded .The energy band gap of the...

ZnO nanorod was prepared by microwave assisted method. The crystal structure of the nano powders were confirmed by X-Ray diffraction analysis and the mean particle size was estimated by the Scherrer,s formula .The surface morphology of the nano particles were analyzed by   using SEM . The absorption spectrum of the material in the UV-Vis range was recorded .The energy band gap of the...