This PDF file contains the front matter associated with SPIE Proceedings Volume 7487, including the Title Page, Copyright information, Table of Contents, aand the Conference Committee listing.

In this paper we report on the use of two solution-processable polymeric and molecular n-channel semiconductors for the fabrication of transistors and CMOS inverters by gravure printing and inkjet printing. Furthermore, the injket-printed TFT/invertor stability characteristics are analyzed and discussed.

We report on the characteristics of a host-guest lasing system obtained by co-evaporation of an oligo(9,9-diarylfluorene) derivative named T3 with the red-emitter 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye (DCM). We demonstrate that the ambipolar semiconductor T3 can be implemented as active matrix in the realization of a host-guest system in which an efficient energy transfer takes place from T3 matrix to the lasing DCM molecules. We performed a spectroscopic study on the system by systematically varying the DCM concentration in the T3 matrix. Measurements of steady-state photoluminescence (PL), PL quantum yield (PLQY) and amplified spontaneous emission (ASE) threshold are used to optimize the acceptor concentration at which the ASE from DCM molecules takes place with the lowest threshold. Organic light-emitting diodes (OLEDs) implementing the DCM:T3 host-guest system as recombination layer are fabricated for verifying the optical properties of the optimised blend in real working devices. Indeed, the very low ASE threshold of T3:DCM makes the investigated blend an appealing system for use as active layer in lasing devices. In particular, the ambipolar charge transport properties of the T3 matrix and its field-effect characteristics make the host-guest system presented here an ideal candidate for the realization of electrically-pumped organic lasers.

Several applications of the thermoluminescence (TL) technique for investigations of mechanisms of charge carrier trapping and recombination in electroluminescent polymers which are used for construction of various opto-electronic devices are described. The presented TL studies were focused on polymers emitting blue light, because such emissive materials are requested to realize the white-light-emitting OLEDs or RGB-displays. We have investigated wide band-gap conjugated polymers and also non-conjugated polymers: series of polyfluorenes (homo- and copolymers) and poly(9- vinylcarbazole), neat and doped with low-molecular-weight dopants. The dopants were introduced in order to improve the charge carrier transport and also the to modify the recombination processes. It is shown, that the spectrally resolved thermoluminescence studies, especially when performed in a broad temperature range allow to characterise the nature of the trapping sites and of the recombination centres and to identify the mechanisms responsible for transfer of energy in the investigated materials.

Laue diffraction with x-rays is common to determine symmetry and crystal structure of natural crystals. Extension of the method towards visible light failed so far due to lack of crystals in nature with lattice parameters in the range of visible light. Nowadays artificially three-dimensional crystals known as photonic crystals (PCs) are available. However, in contrast to x-rays diffraction from small crystals described by the kinematic scattering approach, scattering of visible light from PCs suffers from the large contrast and the tensor character of refractive index originating multiple scattering of probing light. In this paper we show the Laue scattering with visible light at PCs with internal refractive index contrast less then 1%. The Laue pattern shows colour separation and displays the crystal symmetry. Scattering curves of individual Laue spots taken with monochromatic light can be well described by kinematic scattering. Both results demonstrate the applicability of such crystals for spectral filtering.

In the large family of polymers, the azobenzene derivatives represent one fascinating materials class, along with stylbene and azomethinic derivatives. This interest is explained by combination of the properties of anisotropy with the photoinduced behaviors. The photoinduced birefringence, relief grating, the high optical nonlinearity resulted from the sin-anti isomerism, molecular reorientation, the exceptional stability to writing and erasing by laser radiation, are just the most important arguments for their usage of these polymeric architectures in the NLO field as: LCD, chemical sensing, devices for storage and transmission of information . This presentation covers the development and characterization a new series of materials from viewpoint of: -Modification of the polymer materials by the chemical transformation of the "common" polymer support an underlining: photorefractivity, NLO properties -Utilization of these polymers as components in guest-host materials preparation.

We propose a microscopic theory of light-induced deformation of side-chain azobenzene polymers using a statistical model which takes the chemical architecture of azobenzene macromolecules explicitly into account. The theory provides the values of the light-induced stress larger than the yield stress. This result explains a possibility for the inscription of surface relief gratings in glassy side-chain azobenzene polymers. We show that the photo-elastic behavior of azobenzene polymers is very sensitive to their chemical structure. Depending on the chemical structure, a sample can be either stretched or uniaxially compressed along the polarization direction of the linearly polarized light. For some chemical structures, elongation of a sample demonstrates non-monotonic behavior with the light intensity and can even change its sign (a stretched sample starts to be uniaxially compressed). These results are in agreement with experiments and recent computer simulations.

As size requirements and pixel viabilities for mid-wavelength infrared (MWIR) focal plane arrays (FPAs) continue to increase, larger InSb substrate diameters are of significant interest. To improve resolution and sensitivity requirements for high performance infrared focal plane array (IRFPA) imaging systems in the 1-5.4 μm region (77°K), the surface of new larger diameter (150mm) InSb substrates must meet or surpass stringent demands. The scale-up to 150mm InSb has necessitated changes in processing and finishing parameters, as device layer growth by epitaxy or other means often requires a surface roughness average (R_a)~0.1 nm. This study compares two different CMP finishes for new 150mm diameter InSb wafers and examines their suitability for IRFPA applications. InSb surface quality was examined by molecular beam epitaxy (MBE), reflective high energy electron diffraction (RHEED), atomic force microscopy (AFM), thermal X-ray spectroscopy (TXPS), and multiple crystal x-ray diffraction (XRD) for two distinct CMP finishes on InSb(111)B substrates from the same crystal boule. This study has shown that differences result in thermal desorption properties with the CMP process, consistent with differences in surface smoothness and oxide composition. Better surface composition and crystallinity were produced with a modified CMP process for the 150mm diameter crystals. We conclude that the differential ratio between the pH, the oxidizer percentage, and the buffering percentage of the modified CMP process is a benefit to larger diameter InSb IRFPA applications.

We have performed Hyper-Rayleigh Scattering (HRS) experiments to measure the quadratic hyperpolarizability of several natural amino acids, in particular tryptophan and tyrosine. Values of (29.6+/-0.4)x10^-30 esu for tryptophan and (25.7+/-0.03)x10^-30 esu for tyrosine have been found. We have then investigated the dependence of the quadratic hyperpolarizability of tryptophan-rich short peptides as a function of the number of tryptophans in the sequence. The experimental findings indicate that the resulting quadratic hyperpolarizability in these peptides cannot be assumed as the mere coherent superposition of the hyperpolarizabilities of the tryptophans contained in the peptide. Our results unambiguously demonstrate that there must be strong interactions between the tryptophans contained in these short peptides. We have also investigated the case of the collagen triple helix. A second order hyperpolarizability of (1.25+/- 0.05)x10^-27 esu for rat-tail type I collagen has been measured. In this case, we have been able to model this effective quadratic hyperpolarizability by summing coherently the nonlinear response of elementary moieties forming the triple helix, as opposed to the previous case of the tryptophan-rich peptides.

Collagen is a major protein of the extracellular matrix that is characterized by triple helical domains. It plays a central role in the formation of fibrillar and microfibrillar networks, basement membranes, as well as other structures of the connective tissue. Remarkably, fibrillar collagen exhibits efficient Second Harmonic Generation (SHG) so that SHG microscopy proved to be a sensitive tool to probe the three-dimensional architecture of fibrillar collagen and to assess the progression of fibrotic pathologies. We obtained sensitive and reproducible measurements of the fibrosis extent, but we needed quantitative data at the molecular level to further process SHG images. We therefore performed Hyper- Rayleigh Scattering (HRS) experiments and measured a second order hyperpolarisability of 1.25 10^-27 esu for rat-tail type I collagen. This value is surprisingly large considering that collagen presents no strong harmonophore in its aminoacid sequence. In order to get insight into the physical origin of this nonlinear process, we performed HRS measurements after denaturation of the collagen triple helix and for a collagen-like short model peptide [(Pro-Pro- Gly)₁₀]₃. It showed that the collagen large nonlinear response originates in the tight alignment of a large number of weakly efficient harmonophores, presumably the peptide bonds, resulting in a coherent amplification of the nonlinear signal along the triple helix. To illustrate this mechanism, we successfully recorded SHG images in collagenous biomimetic matrices.

LiInSe₂ is one of the few (in the meanwhile 6) non-oxide nonlinear crystals whose band-gap (2.86 eV) and transparency enabled in the past nanosecond optical parametric oscillation in the mid-IR without two-photon absorption for a pump wavelength of 1064 nm. However, the first such demonstration was limited to the 3.34-3.82 μm spectral range with a maximum idler energy of 92 μJ at 3.457 μm for a repetition rate of 10 Hz. Now we achieved broadly tunable operation, from 4.65 to 7.5 μm, with a single crystal, reaching maximum idler pulse energy of 282 μJ at 6.514 μm, at a repetition rate of 100 Hz (~28 mW of average power).

The rapid development of frequency-tunable pulsed lasers up to telecommunication wavelengths (1400-1600 nm) led to the design of new materials for nonlinear absorption in this spectral range. In this context, two families of near infra-red (NIR) chromophores, namely heptamethine cyanine and aza-borondipyrromethene (aza-bodipy) dyes were studied. In both cases, they show significant two-photon absorption (TPA) cross-sections in the 1400-1600 nm spectral range and display good optical power limiting (OPL) properties. OPL curves were interpreted on the basis of TPA followed by excited state absorption (ESA) phenomena. Finally these systems have several relevant properties like nonlinear absorption properties, gram scale synthesis and high solubility. In addition, they could be functionalized on several sites which open the way to numerous practical applications in biology, solid-state optical limiting and signal processing.

We present here novel easily processible organic-inorganic nanocomposites suitable for holographic fabrication of diffraction optical elements (DOE). The nanocomposites are based on photocurable acrylate monomers and inorganic nanoparticles (NP). The compatibility of inorganic NP with monomers was achieved by capping the NP surface with proper organic shells. Surface modification allows to introduce up to 50wt.% of inorganic NP in organic media. Depending on the NP nature (metal oxides, phosphates, semiconductors, noble metals) and their properties, the materials for both efficient DOE and multifunctional elements can be designed. Organic-inorganic composites prepared have been successfully used for the effective inscription of periodic volume refractive index structures using the holographic photopolymerization method. The nanocomposite preparation procedure, their properties and optical performance of holographic gratings are reported. The use of functional NP makes it possible to obtain effective holographic gratings having additional physical properties such as light-emission or NLO. Some examples of such functional polymer-NP structures and their possible application fields are presented. The combination of easy photo-patterning of soft organic compounds with physical properties of inorganic materials in new nanocomposites and the flexibility of the holographic patterning method allow the fabrication of mono- and multifunctional one- and multi-dimensional passive or active optical and photonic elements.

We report on ZnGeP₂ and AgGaS₂ crystal growth and improvement of optical transparency by annealing. Good optical quality single-crystal samples with size up to 5×5×20 mm³ were cut from our ingots, allowing to demonstrate efficient optical parametric oscillation with ZnGeP₂ and to carry out first difference-frequency generation experiments with AgGaS₂.

Gelatin and DNA are abundant natural products with very good biodegradation properties and can be used to obtain acetic acid or LiClO₄-based gel polymer electrolytes (GPEs) with high ionic conductivity and good stability. This article presents the results of the ionic conductivity measurements of GPEs membranes based on crosslinked and plasticized gelatin and on plasticized DNA as well as on inserted/extracted charge density of electrochemical devices (ECDs) obtained with these samples. The membranes were analyzed by impedance spectroscopy, UV-Vis spectroscopy and the ECDs by charge density measurements, respectively. At room temperature the measured ionic conductivity of the membranes is in the range of 10^-4-10^-5 S/cm. It obeys predominantly an Arrhenius relationship in function of temperature. The ECD with red gelatin changed the color from red to deep red and the ECD with DNA-based electrolyte changes from transparent to blue. The inserted charge density values of these ECDs were of -3.0 mC/cm² for the device with red gelatin and -6.6 mC/cm² for the ECD with DNA-based electrolyte. The reverse potential application promoted a charge extraction and, as consequence, bleaching of the devices. Good ionic conductivity results combined with transparency and good adhesion to the electrodes and promising preliminary results of small ECDs have shown that gelatin and DNA-based GPEs are very promising materials to be used as gel polymer electrolytes in electrochromic devices.

We report the synthesis of five new hybrid polymeric structures obtained by free radical copolymerization of some organic azo-based methacrylate monomers and 3-methacryloxypropyl trimethoxysilane (MEMO). The copolymers are soluble in common solvents like methylene chloride, chloroform, dichlorbenzene, dimethylsulfoxide, dimethylformamide. The copolymeric structures might be interesting from the point of view of nonlinear optical response due to a rich content in chromophoric units determined by H-NMR spectroscopy. The structures were also characterized by FT-IR spectroscopy, TGA and SEC analysis.