Software design and implementation of a contactless surface sensing NDE scanning system

http://www.worldcat.org/oclc/2860226

Spectral switching control of ultrafast pulses in dual core photonic crystal fibre

The work presented in this paper is a study of an all-optical narrow-band switch in extended spectral area by dual core photonic crystal fibre expressing nonlinear coupler performance. The investigation is focused on the nonlinear propagation of femtosecond pulses in the near infrared spectral region at up to 50 kW peak power which induces spectral broadening through almost two octaves. The mutual effect of nonlinear spectral transformation and field redistribution between the two fibre cores is analyzed by both theoretical and experimental approaches. The simulation of the nonlinear propagation is based on coupled generalized nonlinear Schrödinger equations. A modified numerical model utilizing split-step Fourier method was adapted for dual core fibres. The complex experimental study was accomplished for various input settings such as polarization, intensity and selective coupling into each core and the selective detection of spectra from each core. The presented work encompasses promising results obtained regarding a spectral intensity switch between the two output channels by input intensity or polarization change in the S-band of optical communication systems

Axial spectral scans of polarization dependent third harmonic generation in a multimode photonic crystal fiber

We demonstrate a nondestructive axial scanning technique for the spectrally resolved analysis of femtosecond nonlinear-optical transformation in photonic crystal fibers. This technique is applied to map the generation of a polarization-switched third harmonic of femtosecond Cr:forsterite laser pulses in a multimode silica photonic crystal fiber. Obtained results confirmed the intermodal phase-matching to be responsible for the observed polarization dependent multipeak third-harmonic generation. The axial scans revealed, that it is necessary to distinguish between the low and high energy excitation regime of the fiber sample. The proposed technique allows to measure the spectra of nonlinear signals generated in a photonic crystal fiber as a function of the propagation distance without cutting the fiber

Influence of acidity on the reaction between [PdCl(dien)](+) and L-cysteine or glutathione in the presence of sodium dodecyl sulfate micelles

The reaction mechanism and thermodynamic parameters of the complex formation between [PdCl(dien)](+) and sulfur-containing ligands L-cysteine and glutathione (GSH) were investigated in the presence of sodium dodecyl sulfate micelles in the pH range 0.5-3.5. The reaction rates were determined under pseudo-first-order conditions (ligand in excess) in the temperature range 276-299 K by using the stopped-flow technique. A reaction mechanism was proposed that consisted of at least two parallel paths involving protonated and zwitterionic forms of thiols. The pH effects on reaction rate were interpreted in terms of the electrostatic interactions between the negatively charged micelle surface and different ionic forms of the ligand species. The calculation of pH-dependent activation parameters (Delta H-not equal and Delta S-not equal) revealed the considerable catalytic effects on the rate of complexation. The entropy of activation is strongly negative in the presence and absence of micelles, which is compatible with an associative reaction mechanism. Copyrigh