Search results for "SHG"

Ferrocene-quinoxaline Y-shaped chromophores as fascinating second-order NLO building blocks for long lasting highly active SHG polymeric films

2016

The first example of a Y-shaped ferrocene quinoxaline derivative with a surprisingly high and stable second harmonic generation (SHG) response in composite polymeric films is reported. The interesting quadratic hyperpolarizability values of different substituted Y-shaped chromophores are also investigated in solution by the EFISH technique.

Influence of Ag, Cu dopants on the second and third harmonic response of ZnO films

2009

International audience; Silver- and copper-doped ZnO films were prepared by radio-frequency (RF)-magnetron sputtering on glass and quartz substrates. The influence of dopants content on the microstructural evolution and optical as well as nonlinear optical (NLO) properties were investigated. It has been found that the grain sizes were enlarged with increasing of Ag, Cu dopants amount in ZnO films. The Ag or Cu doping leads to the optical band gap narrowing. Besides, the second-order NLO response of Ag- and Cu-doped ZnO films is lower than that of undoped ZnO film. The second harmonic generation (SHG) efficiency of the ZnO:Ag film was found to be higher than that of the ZnO:Cu film at the si…

Advanced microscopy analysis of the micro-nanoscale architecture of human menisci

2019

AbstractThe complex inhomogeneous architecture of the human meniscal tissue at the micro and nano scale in the absence of artefacts introduced by sample treatments has not yet been fully revealed. The knowledge of the internal structure organization is essential to understand the mechanical functionality of the meniscus and its relationship with the tissue’s complex structure. In this work, we investigated human meniscal tissue structure using up-to-date non-invasive imaging techniques, based on multiphoton fluorescence and quantitative second harmonic generation microscopy complemented with Environmental Scanning Electron Microscopy measurements. Observations on 50 meniscal samples extract…

Synthèse de nouveaux agents bimodaux hydrosolubles pour l'IRM, l'imagerie nucléaire, l'imagerie biphotonique et la génération de second harmonique

2015

The goal of my PhD studies was to synthesize new compounds for possible medical imaging applications. The first part of my thesis focused on the synthesis of heteroleptic ligands to achieve the chelation of two different metals aimed at addressing two types of medical imaging. We first synthesized porphyrins, which are well-known for the chelation of numerous transition metals. We focused on copper, whose copper-64 isotope is a β+ emitter usable in Positron Emission Tomography (PET). These porphyrins have been coupled with a DOTA derivative. This molecule, metallated with gadolinium, is well-known in Magnetic Resonance Imaging (MRI). Our compounds display encouraging relaxivities for MRI ap…

Ultraviolet quasi-phase-matched second harmonic generation in surface periodically poled lithium niobate optical waveguides

2007

The compatibility of low concentration (alpha-phase) proton exchange channel waveguides with electric field surface periodic poling of congruent lithium niobate (SPPLN) crystals has been experimentally demonstrated. With such waveguides, we obtained ultraviolet second harmonic generation (SHG) by first order quasi-phase-matching (QPM), a result made possible by the fabrication, on Z-cut LN crystals, of periodic structures with a pitch down to 750 nm. Nonlinear copropagating QPM-SHG measurements have been carried out on such structures. The pump source was a Ti:sapphire laser with a tunability range of 700-980 nm and a 40 GHz linewidth. We have measured UV continuous wave light at 390 nm by …

Second Harmonic Generation via Random Quasi-phase Matching in a Periodically Poled Lithium Tantalate Waveguide

2011

We observe second harmonic generation via random quasi phase matching in a 1.5μm periodically poled lithium tantalate. The presence of a slab waveguide allows the comparison between bulk and guided wave configurations.

Influence of Ag, Cu dopants on the second and third optical harmonic generation of ZnO films

2009

High bit rate optical pulses sources generation and microstructured chalcogenide fibers characterizations

2011

This memory of thesis s' registered voter in the context of the FUTUR project financed by l' ANR and concerning the development of optical functions for the high bit-rate transmissions in the Network heart and carries on very high rates optical fibers sources generation and the optical chalcogenide microstructured fiber characterization. For this purpose, we study the linear and non-linear characteristics of microstructured chalcogenide fibers conceived and realized in various collaborations within the framework of the ANR FUTUR project. For that a great number of characterizations methods were developed giving a comparison between a standard single mode fiber and these microstructured chal…

NLO properties of polythiophenes galvanostatically electrodeposited on ITO glasses

2008

International audience; A study of nonlinear optical properties of ClO4-doped polythiophenes, galvanostatically electrodeposited on ITO glasses, was carried out using second and third harmonic generation measurements. The effect of the oxidation state of the polymeric films was studied by comparing the nonlinear optical response of oxidised and reduced polythiophenes. Reduced polymeric films show higher values of the second and third order susceptibilities and a lower absorbance in respect to the oxidised ones. The morphology of the polythiophene films was studied by scanning electron and atomic force microscopes.

High bit rate optical pulses sources generation and microstructured chalcogenide fibers characterizations

2011

This memory of thesis s' registered voter in the context of the FUTUR project financed by l'ANR and concerning the development of optical finctions fot the high bit-rate transmissions in the Network heart and carries on very high rates optical fibers sources generation and the optical chalcogenide microstructured fiber charaterization. For this purpose, we study the linear and non-linear characteristics of microstructured chalcogenide fibers conceived and realized in various collaborations within the framework of the ANR FUTUR project. For that a great number of characterizations methods were developed giving a comparison between a standard single mode fiber and there microstructured chalco…