This pdf file contains the Front Matter associated with SPIE Proceedings Volume 7469, including the Title page, Copyright information, Table of Contents, Conference Committee listing, and Introduction.

The Artemis facility for ultrafast XUV science is constructed around a high average power carrier-envelope phasestabilised system, which is used to generate tuneable pulses across a wavelength range spanning the UV to the far infrared, few-cycle pulses at 800nm and short pulses of XUV radiation produced through high harmonic generation. The XUV pulses can be delivered to interaction stations for materials science and atomic and molecular physics and chemistry through two vacuum beamlines for broadband XUV or narrow-band tuneable XUV pulses. The novel XUV monochromator provides bandwidth selection and tunability while preserving the pulse duration to within 10 fs. Measurements of the XUV pulse duration using an XUV-pump IR-probe technique demonstrate that the XUV pulselength is below 30 fs for a 28 fs drive laser pulse. The materials science station, which contains a hemispherical electron analyser and five-axis manipulator cooled to 14K, is optimised for photoemission experiments with the XUV. The end-station for atomic and molecular physics and chemistry includes a velocity-map imaging detector and molecular beam source for gas-phase experiments. The facility is now fully operational and open to UK and European users for twenty weeks per year. Some of the key new scientific results obtained on the facility include: the extension of HHG imaging spectroscopy to the mid-infrared; a technique for enhancing the conversion efficiency of the XUV by combining two laser fields with non-harmonically related wavelengths; and observation of D3⁺ photodissociation in intense laser fields.

The output performances of a compact, passively Q-switched Nd:YAG/Cr⁴⁺:YAG laser were investigated using single crystals and poli-crystalline ceramics Nd:YAG with doping level between 1.0 and 2.0-at.% Nd, and single crystals and poli-crystalline ceramics Cr⁴⁺:YAG with various initial transmission. Q-switch laser pulses at 1.06 μm with energies up to 2 mJ and duration below 1 ns were realized at a pump repetition rate of 10 Hz. An all-ceramics Nd:YAG/Cr⁴⁺:YAG laser could be a solution for ignition of automotive engines. The optical intensity of a laser pulse with ns duration that induces optical air breakdown was determined.

Single crystals of Gd_1-xR_xCa₄O(BO₃)₃ (R³⁺ = Sc³⁺ or Lu³⁺) with large size and good quality have been grown by Czochralski method. The optical birefringence of Gd_1-xSc_xCa₄O(BO₃)₃ and Gd_1-xLu_xCa₄O(BO₃)₃ crystals can be controlled by changing the compositional parameter x. The chemical compositions of the grown crystals were determined and X-ray diffraction measurements have been carried out to characterize the structural changes with compositional parameter x. According to our assumptions, the obtained results demonstrate that two of the grown crystals convert the near-infrared radiation of 800nm into blue-violet light (400nm) by type-I noncritical phase-matching (NCPM) second-harmonic generation (SHG) processes along Y axis.

The cooperative two-photon scattering processes between two resonator modes stimulated by the excited atomic beam, it is studied. It is demonstrated that these collective scattering phenomena between the Stokes and anti-Stokes resonator modes take place due to energy transfer between these fields. The propriety of these fields consisted from Stokes and anti-Stokes photon is described by the Master equation. The numerical solution of this equation describes the statistical transformation of n-Stokes photons in anti-Stokes photons.

Modern glass application needs to move from traditional tempering with only average controlled fragmentation of security glass to computerized controlled fragmentation by developing engineered stress profiles in glass article. The new treatment methods of soda-lime float glass using irradiation by power Nd:YAG laser which is moved by robot will be discussed. The transparency of glass for laser wavelength is one of the problems of glass treatment by laser. Noncontact stress control by light scattering will be shown. The two main objectives of this work will be discussed: 1. Glass treatment by power laser beam directed to secure glass production; 2. Control methods of residual stress into float glasses treated by laser.

This paper presents an experimental study of the ablation-plasmas and of the craters generated by focusing visible nanosecond laser pulses at normal incidence on a solid target of Er³⁺-doped Ti:LiNbO₃, in atmospheric air. The laser irradiance was varied in the range of 0.25 to 2.5 TW/cm², which is close to the plume-ignition threshold. The spatial variation of the neutral Li lines and of the temperature along the axial direction within the plasma plume was evaluated by scanning axially the plume image with a fiber that is coupled at the spectrometer entrance. The results indicate that the intensity of the neutral Li lines increases when increasing the distance from the target's surface. The plasma temperature calculated by accounting for these lines intensities is almost constant (~14000 K) being non-dependent on laser-irradiance and distance from the target. The spectroscopic study is augmented with an optical microscopy study of the ablated craters in order to determine the correlation between the ablation rate in multi-pulse regime and the plasma spectrum. The results indicate that monitoring the plasma spectrum at a fixed position above the target surface the lines intensity decrease with pulse number, probably due to the confinement of the plume into the deep crater that are drilled in multi-pulse regime.

A general synthetic strategy for the synthesis of nanocrystals of both visible and near infrared emitting materials is introduced. Further, the potential for these materials to be employed in a wide variety of applications is discussed.

Using the theory of open systems based on completely positive quantum dynamical semigroups, we describe the dynamics of entanglement for a system consisting of two uncoupled harmonic oscillators interacting with a thermal reservoir. Using Peres-Simon necessary and sufficient criterion for separability of two-mode Gaussian states, we describe the evolution of entanglement in terms of the covariance matrix for a Gaussian input state. For some values of the temperature of environment, the state keeps for all times its initial type - separable or entangled. In other cases, entanglement generation, entanglement sudden death or a repeated collapse and revival of entanglement take place. We analyze also the time evolution of the logarithmic negativity, which characterizes the degree of quantum entanglement.

In this work, we demonstrate optical functionalities obtained with CdTe nanocrystals embedded in polystyrene. These functionalities are based on our experimentally observed large, saturable, and controlled nonlinear optical properties of CdTe nanocrystals, in the case of strong quantum confinement and near resonant interaction with the excitation light. Our investigation considers the optical limiting functionality, presenting experimental proof of concepts. These types of functionalities are of special interest for integrated optical quantum dots devices with applications in imaging and telecommunications.

If coherent light is incident on a suspension containing nanoparticles, the result of the far field interference is a "speckled" image. As a consequence of the complex Brownian motion the speckle image is not static but presents time fluctuations. A computer code to simulate the dynamics of the coherent light scattering on nanofluids was written, tested and used.

In this paper we present new results concerning the optical and morphologic properties of YVO₄:Eu red nanophosphor prepared by a precipitation method and subsequently annealed in air at various temperatures. We monitored the morphologic changes induced by the thermal treatments using the optical spectroscopy (reflectance and luminescence spectra), XRD and electron microscopy. The annealing leads to an increase of the particle size and improvement of the order of the crystalline lattice of YVO₄. The annealing at 800°C produces the sample with the highest luminescence intensity.

In this paper, we study the dependence of effective optical linear and nonlinear refractive indices of nano-porous silicon layers on crystalline silicon substrates on fill fraction, at different light wavelengths in visible and near-infrared. Simple approximative formulae, in the frame of Bruggeman's formalism, that describe the dependences of effective optical linear and nonlinear refractive indices of nano-porous silicon on fill fractions and on wavelength, in the range of 620 - 1000 nm, are derived. Experimental results with reflection intensity scan show a good agreement with the data provided by our formulae and the exact results of Boyd-Bruggeman's formalism for the third order nonlinearity, in the case nanoporous silicon with different porosity and at light wavelengths in the mentioned spectral range.

Semiconductor quantum dots are nanometer-sized crystals with unique photochemical and photophysical properties that are not available from either isolated molecules or bulk solids. These nanocrystals absorb light over a very broad spectral range as compared to molecular fluorophores which have very narrow excitation spectra. High-quality QDs are proper to be use in different biological and medical applications (as fluorescent labels, the cancer treatment and the drug delivery). In this article, we discuss Fourier transform visible spectroscopy of commercial quantum dots. We reveal that QDs produced by Evident Technologies when are enlightened by laser or luminescent diode light provides a spectral shift of their fluorescence spectra correlated to exciting emission wavelengths, as shown by the ARCspectroNIR Fourier Transform Spectrometer. In the final part of this paper we show an important biological application of CdSe/ZnS core-shell ODs as microbial labeling both for pure cultures of cyanobacteria (Synechocystis PCC 6803) and for mixed cultures of phototrophic and heterotrophic microorganisms.

We predict and experimentally observe the enhancement by three orders of magnitude of phase mismatched second and third harmonic generation in a GaAs cavity at 650 and 433 nm, respectively, well above the absorption edge. Phase locking between the pump and the harmonics changes the effective dispersion of the medium and inhibits absorption. Despite hostile conditions the harmonics resonate inside the cavity and become amplified leading to relatively large conversion efficiencies. Field localization thus plays a pivotal role despite the presence of absorption, and ushers in a new class of semiconductor-based devices in the visible and UV ranges.

A high sensitivity speckle based fiber-optic method for registration of low intensity IR radiation is proposed. The method is based on the effect of variation of the speckle pattern in the far-field of a multimode fiber. IR radiation that falls on a lateral surface of the fiber leads to variation of the speckle image. Computer processing of the speckle image provides information on the amplitude of the perturbation that hits the fiber. An algorithm has been developed for processing of the speckle image and determining of the intensity of IR radiation. The results of computer simulation correlate sufficiently well with experimental ones.

I give a brief overview of recent results in the area of both (2+1-and (3+1)-dimensional localized structures in some selected models in optics and atomic Bose-Einstein condensate. I concentrate on the existence, stability and robustness of these multidimensional localized structures and on the possibility of creation of spatiotemporal optical solitons in various optical settings.

We report soliton waveguide creation in lithium niobate crystals with 405nm c.w. radiation from a low-cost blue-violet laser diode. The high photorefractive sensitivity of lithium niobate at this wavelength allows fast soliton waveguide writing with low light power (~40nW). The writing process of soliton waveguides at this wavelength is experimentally studied. We also show the convenient writing of soliton waveguides arrays in the crystal volume and the good propagation of femtosecond pulses (at 1030 nm) through these waveguides. These waveguides are good candidates for all-optical integrated photonics.

New approach is proposed for estimating the degree of coherence of optical waves. The possibility of transformation of spatial polarization distribution in measured intensity distribution for estimating the degree of correlation of superposing vector waves linearly polarized at the incidence plane is shown.

The influence of the ionic contribution to electro-optic effect in nematic liquid crystals aligned with conducting polymers was investigated. The study has been carried out on symmetric cells filled with nematic liquid crystal 5CB having positive dielectric anisotropy. Planar alignment of the nematic director has been imposed using unidirectional rubbed conducting polymer substrates, namely polypyrrole (PPy) doped with different types of ions. Employing a typical experimental set-up, the intensities of linearly polarized He-Ne light beams, transmitted through each cell when submitted to an external electrical excitation, were measured. Fast electro-optic response times measured at switching off the electric field are probably related to the accumulated charge distributions at nematic-conducting polymer interface.

A general model was built for spatial solitons in photorefractive crystals using the inverse problem in the scattering theory. The inverse problem in the scattering theory is defined knowing the spectral data that characterize the scattering. We present a formalism regarding the use of the inverse method in solving the nonlinear differential equations. Envelope singular analytical solutions (solitons) and asymptotically solutions of the wave equation for integral equation were obtained. The results are in good agreement with the results obtained in other papers.

Wandering of a laser beam in the atmosphere is due to fluctuations of the refractive index of the atmosphere and, having a strong dependence on the path length, is very useful to investigate random or continuous changes of the refractive index during time. First, we describe methods we developed and applied to locally investigate the parameters of turbulence (inner scale, outer scale and structure constant) based on our previous theory of propagation of "thin" beams. Then we describe use of thin beams to investigate the evolution of the refractive index gradient and show experimental results including non stationary and non isotropic conditions.

The native cellular environment represents a crowded system comprising high concentrations of soluble molecules that interact mostly in a nonspecific manner. Some of the macromolecular crowding effects occurring in biological media are conformational changes and macromolecular associations. Most of our knowledge on protein folding and protein-protein interactions was acquired from experiments on proteins in dilute solutions or from theoretical models of isolated proteins in either explicit or implicit solvent. Here we present a 50% w/w bovine serum albumin (BSA) solution model that comprises two solute molecules included in a single water box. We determined the vibration spectrum of the 50% w/w BSA solution using THz spectroscopy and we calculated the theoretical THz spectrum. We observed a good correlation between the experimental and theoretical spectra for the frequency range of 0.3 - 1.5 THz. We also investigated the contribution of each BSA molecule to the solution THz spectrum by simulating THz spectra of the two BSA molecules from the solution model and water, each accounting for a 50% w/w BSA solution. The spectra appear to be similar. As the two molecules in our solution model have different conformations, we investigated the importance of the apparently insignificant differences between simulated THz spectra of the two proteins. We found that the differences should be considered significant, as they reflect differences between the flexibility of the two BSA molecules.

Light scattering on particles having the diameter comparable with the wavelength is accurately described by the Mie theory and the light scattering anisotropy can conveniently be described by the one parameter Henyey Greenstein phase function. An aqueous suspension containing magnetite nanoparticles was the target of a coherent light scattering experiment. By fitting the scattering phase function on the experimental data the scattering anisotropy parameter can be assessed. As the scattering parameter strongly depends of the scatterer size, the average particle diameter was thus estimated and particle aggregates presence was probed. This technique was used to investigate the nanoparticle aggregation dynamics and the results are presented in this work.

The single act light scattering anisotropy is conveniently described using the Henyey-Greenstein phase function when the scattering centers dimension is comparable or bigger than the wave length. When the concentration increases, a different phase function can be used. For a certain scattering angle the calculated light scattering intensity variation with the optical depth of the target is analyzed and compared with the experimental data recorded on mud in aqueous suspension. The results suggest a very fast method for measuring very small concentration in suspensions, in the range of μg/l.

Urban areas are currently among the most rapidly changing types of land cover on the planet. Remote sensing imagery can provide a timely and synoptic view of urban land cover, as well as a means to monitor change in urbanizing landscapes and to compare urban environments globally. To understand the ecology of urban systems, it is necessary to quantify the spatial and temporal patterns of urbanization, which often requires dynamic modeling and spatial analysis. Based on Spectral Mixture Analysis, this paper aims to provide a spatio-temporal analysis of urban structure for Bucharest urban area based on multi-spectral and multi-temporal satellite imagery (LANDSAT TM, ETM; MODIS, IKONOS) over 1989 - 2007 period. Accurate maps of urban tree and other surface cover types can provide critical information to better understand urban ecosystems and help improve environmental quality and human health in urban areas.

Multifunctional role of forest is revealed by: short and long-term responses and reactions to a fast changing environment, forest being able to provide ecological and social services, to assure a forest-wood chain that meet the needs for forest based goods and products. Forest vegetation cover characteristics, including land cover and phenology, affect processes such as water cycle, absorption and re-emission of solar radiation, momentum transfer, carbon cycle, and latent and sensible heat fluxes.The climate system responds in complex ways to changes in forcing that may be natural or humaninduced. Drastic climate change over the last two decades has greatly increased the importance of global environmental study. In frame of this research, forest changes monitoring through satellite remote sensing can continually observe various surface processes playing an increasingly important role in large-scale environmental monitoring. Thresholding based on biophysical variables derived from time trajectories of satellite data is a new approach to classifying forest land cover changes. The input data are composite values of the Normalized Difference Vegetation Index (NDVI). Fusion technique was applied to Landsat TM, LANDSAT ETM, and IKONOS imagery for a forested area, Cernica, placed at the North Eastern part of Bucharest town, Romania, over a period 1989-2007. Specific aim of this paper is to assess, forecast, and mitigate the risks of climatic changes on forest systems.

We present novel optical system capable for fast acquisition of two-dimensional distribution of reflection spectra with high spatial resolution. It is based on a subspace vector model of surface reflections. The system consists of a computer controlled set of light-emitting diodes (LED) and a monochrome CCD camera. Spatial distribution of reflection spectra is acquired in the compressed form. These compressed data can be directly used for accurate classification or recognition of different parts of the surface under study. We demonstrated experimentally that 2D distribution of spectral reflectance from the object surface can be captured within 140ms. Such a fast instrument of multispectral imaging could be extremely useful particularly for researchers who study living biological objects.

CuIn_1-xGa_xS₂ (CIGS2) thin-films for solar cells were prepared by rf-magnetron sputtering and were deposited on glass substrate. These films were prepared using a stepwise process consisting of succesive deposition of CuInGa (d = 1500 nm) and ZnS (d = 200 nm) layers. Each layer was structurally characterized by X-ray diffraction and atomic force microscopy. The microstructural and optical properties of CIGS2 component films of the solar cell in comparison with those of ZnS and CuInGa films separately deposited onto glass substrates under the same conditions, were studied. Transmission spectra of our thin films are strongly influenced by deposition conditions and nature of the support material and they were recorded for each component film and CIGS2 solar cell. Thin films, rf magnetron sputtering, CIGS2 solar cell, Surface roughness, Optical pr

This paper describes the experimental results in micro-machining technology which were performed by using a 248 nm KrF excimer laser, beam homogenizers, mask image, projection lens and a five axis computer numerical controlled (CNC) equipment. The optical system is composed by two beam homogenizers of different focal lengths, a condenser lens that takes and reshapes the laser beam, the field lens that collimates the beam, the mask that defines the image and the projection lens. The shape of the mask is kept identical on the target in the micrometric scale. The components which were manufactured are intended to be used to develop micro-motors and gyroscopes.

The paper approaches the optical choppers for two of their possible functions, i.e. attenuators and modulators. An overview of the different types of optical attenuators is also achieved. Constructive and design considerations of choppers are discussed. Various possible configurations of rotating wheels are considered, in relationship with the diameter of the light bundle, in order to produce a certain signal modulation, i.e. a required profile of the transmitted flux. A source of errors regarding the use of these devices is discussed. We describe an adjustable rotating wheel that we have designed and produced to allow for the adjustment of the geometrical parameters of chopper for experiments.

This paper reports some modelling results concerning a novel Er³⁺:Ti:LiNbO₃ optical waveguide directional coupler. Based on the mode coupling theory we evaluated the coupling coefficient between the straight and curved waveguides of the directional coupler. Also, using a quasi-two-level model in the small gain approximation and the unsaturated regime in this paper we report some original results concerning the evaluation of the spectral optical gain, spectral noise figure and spectral signal-to-noise ratio in the bent Er³⁺:Ti:LiNbO₃ waveguide of the directional coupler pumped near 1484 nm performed for erfc, Gaussian and constant profile of the Er^3_ ions in LiNbO₃ crystal.