This PDF file contains the front matter associated with SPIE Proceedings Volume 8882, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Functionalization of deoxyribonucleic acid (DNA) with surfactants, photosensitive and conductivity increasing molecules as well as thin film processing is reviewed and discussed. The comparative spectroscopic studies of chemical and photothermal stability of several chromophores show a better stability in DNA-cetyltrimethylammonium (CTMA) surfactant complexes than in polycarbonate (PC) or poly(ethylene glycol) (PEG) matrices. Also the optical damage threshold in nanosecond pulsed laser illumination is higher in thin films of bio-macromolecules such as DNA, DNACTMA, collagen than in PC. The electrical conductivity of doped DNA based systems exhibits a typical ionic character and can be improved by an appropriate doping. Practical applications of DNA based complexes are reviewed and discussed.

For many decades, it has been accepted that the resolution of a lens-based optical microscope is limited to about d =λ (2 NA) < 200 nm. The discovery in the 1990’s that elementary transitions between the states of a fluorophore can be used to eliminate the limiting role of diffraction has led to lens-based light microscopy concepts with resolution down to the nanometer scale^1,2. Currently, all far-field fluorescence nanoscopy (superresolution) concepts that have found wider application share a common enabling element: they modulate the fluorescence capability of adjacent features such that they fluoresce sequentially^3,4.

Green (525, 550 nm, Er³⁺ transition (²H_11/2, ⁴S_3/2) → ⁴I_15/2), red (660 nm, ⁴F_9/2 → ⁴I_15/2), blue (440 – 490 nm, ⁴F_3/2,5/2,7/2 → ⁴I_15/2), violet (410 nm, ²H_9/2 → ⁴I_15/2), and near ultraviolet (380 nm, ⁴G_11/2 → ⁴I_15/2) upconversion luminescence in langatate (La₃Ga_5.5Ta_0.5O₁₄) doped with erbium and ytterbium ceramic sample, synthesized by solid state reaction in air, was obtained by pumping at 973 nm. Yb³⁺ – Er³⁺ energy transfer processes accounting for population of the emitting levels are discussed. The measured lifetimes of the emitting and intermediate Er³⁺ levels are compared with the radiative lifetimes estimated with the Judd-Ofelt theory.

Numerical simulation results obtained in investigating the generation of laser pulses with 1.55 μm wavelength generated by an Er³⁺, Er³⁺-Yb³⁺ or Cr³⁺-Yb³⁺-Er³⁺ laser or fiber laser oscillator operated in passive optical Q-switching regime are presented. Three types of passive optical Q-switch cell are investigated: the usual one based on Co²⁺ or UO² embedded in different hosts; the second consisting of Co²⁺ nano-crystals. The spectroscopic characteristics of these Q-switch cells are analyzed and correlated with criteria obtained with a numerical simulation procedure based on solving a rate equation system.

Laser pulses at 1.06 μm with 2.5-mJ energy and 3.1-MW peak power have been obtained from a composite, all polycrystalline ceramics, passively Q-switched 1.1-at.% Nd:YAG/Cr⁴⁺:YAG laser that was quasi-continuous-wave pumped with diode lasers. Single-pass frequency doubling with LiB₃O₅ nonlinear crystal at room temperature yielded green laser pulses at 532 nm with energy of 0.36-mJ and 0.45-MW peak power; the infrared-to-green conversion efficiency was 0.27.

Nonlinear optical phenomena which dominate the interaction of tightly focused femtosecond laser beams with materials are discussed. Different femtosecond laser based techniques for material processing such as laser ablation, two-photon photo-polymerization, and material surface nano-structuring are described. For the computer controlled micro-processing of materials, near-infrared Ti:sapphire femtosecond lasers, with nano-Joule/micro-Joule pulse energy, were coupled with direct laser writing workstations. Laser fabricated micro-nanostructures and their applications are presented.

We report on the synthesis of advanced nanostructured hydroxyapatite thin films onto 3D titanium (Ti) mesh substrates by Pulsed Laser Deposition method. Morphological and structural investigations as well as pull-out tests proved the stoichiometric transfer of crystalline hydroxyapatite (HA) films along with their good adherence. In vivo tests were performed on 12 patients (six with simple Ti mesh, six with Ti mesh biofunctionalized with HA). The tomodensitometry analysis of the cranial control scans evidenced the process of osseogenesis. For four patients with implanted HA/Ti mesh structures, the modification of the value obtained on Hounsfield scale was observed at the level of implant, proving the progress of osseointegration. We conclude that the structures exhibit excellent bonding strength and functionality, and are suitable for neurosurgical applications.

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of continuous variable quantum entanglement and quantum discord for a system consisting of two non-interacting non-resonant bosonic modes embedded in a thermal environment. We study the time evolution of logarithmic negativity, which characterizes the degree of entanglement, and show that in the case of an entangled initial squeezed thermal state, entanglement suppression takes place for all temperatures of the environment, including zero temperature. We analyze the time evolution of the Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and show that discord decays asymptotically in time under the effect of the thermal bath. We describe also the time evolution of classical correlations.

Non-spherical dielectric microparticles were suspended in the water-filled cell and exposed to the coherent Gaussian light beam with switchable state of polarization. When the beam polarization is linear, the particles were trapped at certain off-axial position within the beam cross section. After switching to the right (left) circular polarization, the particles performed spinning motion in agreement with the angular momentum imparted by the field, but also they were involved in the orbital rotation around the beam axis, which in previous works [Y. Zhao et al, Phys. Rev. Lett. 99, 073901 (2007)] was treated as an evidence for the spin-to orbital angular momentum conversion. Since in our situation the moderate focusing of the beam excluded possibility of such a conversion, we treat the observed particle behaviour as a demonstration of the macroscopic “spin energy flow” predicted by the theory of inhomogeneously polarized paraxial beams [A. Bekshaev et al, J. Opt. 13, 053001 (2011)].

This research is motivated by our interest in fabrication of plasmonic single metal layer and metal-dielectric multilayer nanolenses with resolution exceeding the diffraction limit. Nanolayers of noble metals are evaporated in an e-beam physical vapour deposition machine on smooth substrates at temperatures controlled in the range 90÷300 K. For dielectric nanolayers ion assisted deposition is used. Thin films of Ag are deposited on polished fused silica and sapphire substrates. To reduce island growth substrate cooling and wetting layers are used. Our aim is to find deposition conditions when influence of thermal expansion mismatch on smoothness of deposited layers can be diminished. Quality of surfaces is assessed using standard deviation of average roughness measured with atomic force microscope for films deposited at different rates and different temperatures.

In this work, we study some periodically nanostructured silicon-on-insulator samples that could be considered as a composite material and described by effective medium theory. We present our theoretical and experimental studies on effective linear refractive index and third-order optical nonlinear response of silicon-on-insulator with 1D periodic nanostructures. Using reflection intensity-scan method in continuous wave regime (at 808 nm wavelength) and in femtosecond pulsed laser regime (at 775 nm wavelength and 140 fs pulse duration), we show that the thermal effects and electronic third-order optical nonlinearities are larger than those obtained on bulk silicon and unstructured SOI. Our results may be important for ultrafast silicon photonics.

In this paper, we show our preliminary results in the investigation of the nonlinear optical properties of dye sensitized DNA. We are measuring the nonlinear refractive indices of the DNA with cetyltrimethylammonium (CTMA) surfactant, doped with Rhodamine 610 dissolved in butanol. The measurements are made using the Double Z-Scan method using a femtosecond laser at 1030nm as light source working in mode-locked and un-mode-locked regime respectively for discriminating fast nonlinearities from the slow ones.

Preliminary results obtained in investigating a plane electromagnetic wave incident on a metal nanowire grating formed on a dielectric substrate, using FEM, are presented. The numerically simulated model is developed considering Cu, Au, Ag or other metal nanowire having a diameter of 40 nm - 800 nm, formed on dielectric substrates with a refractive index between 1.4 and 2.4. The transmission and reflection coefficients for refraction, specular reflection and first order diffraction are computed. The cases of dielectric substrate with metallic layers of different thicknesses deposited on the opposite side are also investigated.

A ghost imaging setup having a spontaneous down conversion (SPDC) entangled photon source is considered. The experimental results prove that a change of the object reflection coefficient modifies the idler single count rate. An infrared laser acting as “signal reflected photons” source intensifies the idler single count rate. A crude explanation of this effect could be the stimulated SPDC photon pair generation. Fascinating applications arise: stimulated high intensity SPDC entangled photon sources.

Three different histograms of the instantaneous Stehl ratio, measured from three adaptive optics telescopes, were recently published (J Opt. Soc. Am, November 2010) by Gladysz et al., in a paper on the use of the probability density function (PdF) of adaptive optics for exoplanets detection. Their PdFs present values of the skewness coefficients of different signs. Surprisingly they are the same kind of histograms that we found many years ago, measuring the time evolution of the intensity at the focus of a large lens collecting an atmospherically degraded laser beam, many years ago. We describe the explanation we gave of our results (Ciolli, Consortini et al., Applied Optics, May 1977) and suggest here a similar one.

Present performance analysis of optical imaging systems based on results obtained with classic one-dimensional (1D) resolution targets (such as the USAF resolution chart) are significantly different than those obtained with a newly proposed 2D target [1]. We hereby prove such claim and show how the novel 2D target should be used for correct characterization of optical imaging systems in terms of resolution and contrast. We apply thereafter the consequences of these observations on the optimal design of some two-dimensional barcode structures.

An additional possibility for estimating the degree of coherence of interacting fields when classic methods of diagnostics cannot be applied is offered.

The spatiotemporal optical solitons (alias nonlinear “light bullets”) are nondiffracting and nondispersing wave packets propagating in nonlinear optical media. The three-dimensional spatiotemporal solitons are localized (self-guided) in two transverse (spatial) dimensions and in the direction of propagation due to the balance of anomalous group-velocity dispersion of the medium in which they form and nonlinear self-phase modulation. The formation of fully threedimensional spatiotemporal optical solitons in two-dimensional photonic lattices was reported in recent experiments. Also, linear light bullets, which are robust and versatile localized wave packets combining Bessel beams in the transverse plane with temporal Airy pulses have been reported experimentally. A brief up-to-date survey of recent theoretical and experimental studies of the formation, stability and robustness of linear and nonlinear light bullets in various physical settings is given.

Recently it was shown that soliton waveguides in lithium niobate can be recorded very fast at 405 nm wavelength. We analyze the mode profile of soliton waveguides recorded at 405 nm using different external electric fields and different writing beam polarizations. We discuss the advantages of recording at this wavelength when comparing with the recording process at 532 nm.

The two-photon and scattering resonances between the spontaneous emissions of the two- and single- photon transitions of the three-level inverted radiators in the Ξ, V configurations and the system of two-level radiators D, inverted relatively the dipole forbidden transition are revised. This approach opens the new possibilities in the manipulation of the decay process and generation of the entangled photon pairs. The correlation between the V and Ξ cascade three-level subsystems on the two-photon transitions of dipole forbidden radiators is studied, taking into consideration the cooperative scattering and two photon resonances through the vacuum field. One of them corresponds to the situation when the total energy of emitted photons by three level dipole-active radiator in the cascade configuration enters into the two-photon resonance with the dipole-forbidden transitions of second atom. Another effect corresponds to the scattering situation, when the difference of the excited energies of the two dipole-active transitions of V three level radiator are in the resonance with the dipole-forbidden transitions of the second one. These effects are accompanied with the interferences between single- and two-quantum collective transitions of the inverted radiators from the ensemble. The two particle collective decay rate is defined in the description of the atomic correlation functions.

In this paper, we propose optical tweezers based on a biaxial crystal. To control the movement of opaque particles, we use the shift polarization interferometer. The results of experimental study of laser tweezers are shown. We demonstrates movement of a microparticle of toner using singular-optical trap, rotate a particle due to orbital momentum, conversion of two traps when changing the plane of polarizer transmission and converging of two traps.

This paper produce formulae for the power reflection and transmission coefficients of a uniaxial thin film sandwiched between two isotropic media and the necessary intermediate formulae of the field reflection and transmission coefficients at the planar interface between a isotropic and a uniaxial media in explicit form. The formulae obtained are tested successfully using the criteria of conservation of energy and the conservation of the form of the equations for time reversal.

Spectral patterns of different forest land cover can identify certain pollution compounds, and water stress conditions based on the interaction of photons with the molecular structure of the forest target structure. Based on such methods, the objective of this research was to evaluate and characterize selected forest test area Baneasa- Tunari located in the Northern part of Bucharest metropolitan region, Romania, where the climate and anthropogenic stressors endanger natural and economical values of environment. Based on time-series Landsat TM, ETM, MODIS Terra/Aqua and IKONOS satellite data have been investigated urban forest land cover and forest biophysical parameters (Normalized Difference Vegetation Index- NDVI and Leaf Area Index- LAI) changes over 1990- 2011 period of time. Accuracy of image processing results (spectral classification) was confirmed through in-situ spectroradiometrical analysis of reflectance spectra with portable GER 2600 spectroradiometer.

This work is aimed at ascertaining the possibilities to diagnose and classify phase-inhomogeneous layers (PhIL) of various types (surface-scattering, subsurface-scattering and bulk-scattering ones) by determination values and ranges for changing the statistical (moments of the 1-st to 4-th orders), correlation (autocorrelation functions) and fractal (logarithmic dependences for power spectra) parameters that characterize coordinate distributions for polarization-singular states in PhIL laser images.

Our work is aimed at searching the possibilities to perform diagnostics and differentiation of structures inherent to liquid-crystal networks of blood plasma with various pathologies (health - breast cancer) by using the method to determine the coordinate distributions of phase shifts (phase maps) between orthogonal components of laser radiation amplitudes with the following statistical, fractal and singular analyses of these distributions.

The optical model of polycrystalline networks of myocardium protein fibrils is presented. The technique of determining the coordinate distribution of polarization azimuth of the points of laser images of myocardium histological sections is suggested. The results of investigating the interrelation between the values of statistical (statistical moments of the 1^st-4^th order) parameters are presented which characterize distributions of wavelet-coefficients polarization maps of myocardium layers and death reasons.

Numerical simulation results obtained in investigating laser paint removal from different metal substrates, mainly aluminum and aluminum alloys, are presented. The main purpose of the developed simulation model is to define the laser installation specifications required for an operation that does not affect the substrate on which the paint is deposited. This is an important laser application in aeronautical industry. The developed simulation model considers transverse laser beam intensity distribution and, consequently, the temperature distribution in the processed mechanical component.

Phenothiazine exposed to white light or UV radiation undergoes a variety of reactions that result in the degradation of the parental compound and the formation of new species. Chlorpromazine exposed to the 266 nm laser beam of given energy levels yielded species derived from it, whose number increased with the exposure duration. At distinct time intervals the irradiation products were evaluated by spectrophotometry between 200-1500 nm, Thin Layer Chromatography, and for antimicrobial activity of Chlorpromazine against different test organisms such as Staphylococcus aureus.

Our research is aimed at designing an experimental method of Fourier laser polarization phasometry of the layers of human effusion for an express determining the potentialities of diagnostics of pathological changes in mammary gland basing on polarization analysis of laser images of the biopsy of the uterine wall tissue in order to differentiate benign (fibromioma) and malignant (adenocarcinoma).

To characterize the degree of consistency of parameters of the optically uniaxial birefringent protein nets of blood plasma a new parameter – complex degree of mutual coherence (CDMC) is suggested. The technique of polarization measuring the coordinate distributions of the complex degree of mutual anisotropy of blood plasma is developed.

MODIS Terra/Aqua time-series satellite images and in- situ monitoring of particle matter PM2.5 and PM10 have been used in an effort to qualitatively assess distribution of aerosols in the greater Bucharest area during 2010-2011 period. It was found that PM2.5 and PM10 aerosols exhibit their highest concentration mostly in the central part mainly due to road traffic as well as in the industrialized parts outside of city’s centre. An epidemiological study examining the relationships between adverse health outcomes and exposure to air pollutants in metropolitan agglomeration of Bucharest used ambient air pollution measurements like as PM10 and PM2.5 levels as a proxy for personal exposure levels. The measurements of environmental concentrations of particulate matter air pollutants have been correlated with health effects on respiratory health status of school children in urban/periurban areas of Bucharest.

Climate variability and change are risk factors for climate sensitive activities such as forestry. Managing these risks requires “climate knowledge”, i.e. a sound understanding of causes and consequences of climate variability and knowledge of potential management options that are suitable in light of the climatic risks posed. Thresholding based on biophysical variables derived from time series satellite data is a new approach to classifying forest land cover via remote sensing through use of Normalized Difference Vegetation Index –NDVI and Enhanced vegetation Index- EVI. This paper aims to assess spatio-temporal forest changes through applied time-series Landsat TM, ETM, MODIS Terra/Aqua and IKONOS satellite remote sensing data of Cernica forest area near Bucharest, Romania, during 1990-2011 period. Additional forest biophysical parameter Land Surface Temperature/Emissivity - LST was considered in this paper. This information is complemented by in-situ monitoring data (field measurements, data collection) together with modeling tools (theoretical developments, mathematical and bio-geophysical parameterization, statistics of the main urban structures in their interdependency) and spatial analysis methods.

Various aspects of distributed feedback fiber laser sensors, their interaction with environment and their possible applications are investigated by numerically solving coupled-mode equations system describing the laser field propagation. The developed numerical analysis has the aim to better understand the DFB-FL itself and its interaction with environment in order to be operated as a sensor. The main idea consists in finding out how various environment parameters modify the coefficients of coupled-mode equations describing the laser field propagation through the DFBFL structure.

This paper presents the experimental results on preliminary study of the physical proprieties of the multimode optical fiber in radiation field delivered by electron linear accelerator of the National Research and Development Institute for Laser, Plasma and Radiation Physics (INFLPR). This study is based on the physical degradation effect of the optical fiber due to electron beam exposure measured through dependence of the exposure dose in electron beam and radiation induced attenuation. Optical fiber attenuations were measured before, during and after electron beam exposure. Results show a greater attenuation for multimode optical fiber of lower wavelength.

Experimental study of quasimonochromatic and polychromatic (“white-light”) radiation, that diffracts on very narrow (in order of several wavelength) slit in metallic screen is represented. It is shown that for monochromatic light slit acts similarly to linear analyzer. And for polychromatic light polarization action of a slit is accompanied with a spectral effect, viz. considerable predomination of blue component in total radiation. The chromascopic technique is applied for analyzing this spectral effect.