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
The concept of time refraction is introduced to describe the effects of a sudden change of the optical properties of a dielectric medium. This can be seen as the most elementary process associated with photon acceleration and frequency upshifting. The quantum theory of such a process shows that the initial wave splits into time-transmitted and time-reflected waves propagating in opposite directions after the occurrence of a time discontinuity of the refractive index. The time refraction laws, analogous to the well known Fresnel formulas and Snell's law, are also derived. It is shown that, in quantum terms, time refraction is equivalent to a squeezing transformation.

Abstract
We show how stationary entanglement between an optical cavity field mode and a macroscopic vibrating mirror can be generated by means of radiation pressure. We also show how the generated optomechanical entanglement can be quantified, and we suggest an experimental readout scheme to fully characterize the entangled state. Surprisingly, such optomechanical entanglement is shown to persist for environment temperatures above 20 K using state-of-the-art experimental parameters.

Abstract
We present a new formulation for the direct laser acceleration of electrons in vacuum based on the Hamiltonian theory, Two different regimes for the snow-plowed, accelerated electrons are identified and characterized, the first pertaining to high-intensity and the second to low-intensity pulses, both leading to efficient electron acceleration. Particle energy yields are shown to be independent of the exact shape of the laser pulse and energy gains are estimated.

Abstract
We discuss and compare several concepts of optical cryptographic systems currently being proposed to improve communication security, their strong points and weaknesses. We will focus on approaches based on chaos synchronization.

Abstract
In this paper is described an easy, one-pot synthesis of ZnO hollow spheres with sizes ranging from 300 nm to 500 nm, by spin-coating deposition on aluminum substrate. Simplified models explaining the shape formation based on film-substrate interaction are discussed. The characteristic size and shape of the nanostructures obtained by the described method and the properties of ZnO as a low-cost biocompatible material make this methodology of synthesis interesting for a wide range of applications including optoelectronics, catalysis and (bio)sensors.