Abstract
We discuss a mechanism of generating two separable beams of light with a high degree of entanglement in momentum using a fast and sharp optical boundary. Three regimes of light generation are identified depending on the number of resonant interactions between the optical perturbation and the electromagnetic field. The intensity of the process is discussed in terms of the relevant physical parameters: variation of refractive index and apparent velocity of the optical boundary. Our results suggest a different class of generation entangled light that is robust against thermal degradation by exciting zero point fluctuations using parametric resonant optical modulations.

Abstract
It is shown here that st straightforward procedure can be used to quantize the linearized equations for an electromagnetic field in a plasma. This leads to a definition of an effective mass for the transverse photons, and a different one far the longitudinal photons, or plasmons. Both masses are simply proportional to the electron plasma density. A nonlinear perturbative analysis can also be used to extend the quantization procedure, in order to include the ponderomotive force effects. This leads to the definition of a photon charge operator. The mean value of this operator, for a quantum state with a photon occupation number equal to 1, is the equivalent charge of the photon in a plasma.

Abstract
We propose to use nondegenerate cascaded four-wave mixing processes for efficient high order harmonic generation in plasmas and dielectrics. A simple model is used to estimate the temporal duration and maximum order of the generated harmonics for both a typical laser-produced plasma and a glass slide. In the plasma case, we expect considerable pulse compression, with the production of sub-femtosecond pulses starting from the 8th harmonic.

Abstract
A new method of high-harmonic generation by intense and short laser pulses is proposed. This method is based on the idea that, in quite general situations, a cascade of four-wave-mixing processes can occur. A theoretical model is established and exact analytic solutions are obtained. Examples of possible experiments in low-charged plasmas and in glass are discussed in detail, including the phase-matching conditions, the angular spread of the secondary beams and the pulse durations. Numerical examples of the possible generation of sub-femtosecond pulses are also given.

Abstract
The nonlinear Debye screening associated with the trapped ion population around a negatively charged dust particle immersed in a plasma is considered here. The analogy between the dressed dust particle in a plasma and an atomic system is explored. It is shown that, in certain limits, the system is described by a Thomas-Fermi-type of wave equation.

Abstract
The concepts of time refraction was introduced in recent years, as the temporal analogue of the usual (space) refraction, for waves propagating in non-stationary optical media. We discuss possible experimental configurations for time refraction of low intensity and short laser pulses propagating in optical fibers, and their eventual use in photonics. We generalize our previous work to the case of guided propagation. The expected frequency shifts, amplitudes and shapes of the secondary pulses resulting from time refraction are calculated.