Abstract

Abstract
Definition of channel waveguides on hybrid sol-gel material was demonstrated using a 248 nm UV excimer laser. without mixing organic photoinitiators in the solution preparation step. Thin films fabricated by hydrolysis and polycondensation of methacryloxypropyltrimethoxysilane (MAPTMS) doped with zirconium oxide were deposited by spin-coating on soda-lime glass substrates (n=1.514). Channel waveguides were defined by microlithography and then covered by a protective layer composed of a combination of MAPTMS and tetramethoxysilane (TMOS). Finally, after cutting and polishing, the waveguides were optically characterised.

Abstract
The main objective of this work is to investigate the correlation between meditation stages and the hypnagogic stages of sleep and awakening. It reports the study on the brain electric activity during Yôga Svásthya meditation stages. These data were obtained by means of scalp electroencephalograms (EEGs), and confronted with the stages of meditation and hypnagogic EEG stages. The latter were based on established criteria through the study of the duration of individual occurrences of each of the nine considered hypnagogic EEG stages. Analysis made concerns time, frequency, power and signal amplitude. The results show that meditation stages reach only the first two hypnagogic EEG stages, and the spectral analysis of the EEG confirmed a dominance of rapid rhythms (beta) while the presence of lower ones (delta and theta) are not significant.

Abstract
We describe a new regime of operation where sub-10-fs ultrashort laser pulses with symmetric spectra centered at 800 nm can be directly generated from a prism-dispersion-controlled modelocked Ti:sapphire oscillator that only uses commercially available standard optics.

Abstract
We report on simulation studies of thin plasma foils explosions upon interacting with high-intensity, ultra-short laser pulses. By using a fully relativistic Particle-in-cell code we describe the time-resolved position, momentum and energy of electrons and ions, for laser pulses with durations of tens of fs and intensities ranging from 10(20) W/cm(2) to 10(23) W/cm(2). Results show the generation of a Mev electron beam as well as supra-Mev ions. Ponderomotive Boost and Colombic Explosions are mechanisms used to explain the results.

Abstract
The effect of photon beam splitting in a time-varying medium is described by classical and quantum theoretical models. It generalizes the concept of time refraction, introduced recently by the authors as a natural extrapolation of the usual concepts of refraction and reflection into the time domain. Total time reflection is shown to exist. A sequence of time refraction processes is shown to lead to temporal interference effects. The concept of temporal beam splitter is introduced. Bogoliubov transformations for the temporal beam splitter are derived. Resonant amplification of light by change in time in the optical medium is shown to exist.