Field Of Strong Electromagnetic Wave Research Articles

Radiation from relativistic electrons in "light" and in conventional undulators. Classical and quantum approaches

A photon spectrum of undulator radiation (UR) is calculated in the semi-classical approach. The UR intensity spectrum is determined by an electron trajectory in the undulator neglecting by energy losses for radiation. Using the Planck's law, the UR photon spectrum can be calculated from the classical intensity spectrum both for linear and nonlinear regimes. The radiation of an electron in a field of strong electromagnetic wave (radiation in the "light" undulator) is considered in the quantum electromagnetic frame. Comparison of results obtained by both approaches has been shown that UR spectra in the whole cone coincide with high accuracy for the case x<<1. Characteristics of the collimated UR beam were simulated with taking into account the discrete process of photon emission along an electron trajectory in both kinds of undulators.

Analysis of the nonlinear absorption mechanisms in ablation of transparent materials by high-intensity and ultrashort laser pulses

The mechanisms of nonlinear absorption in transparent materials under irradiation with ultrashort laser pulses are considered theoretically. Nitride semiconductor, sapphire and others transparent dielectrics were investigated. The ablation threshold for these materials is within multi-TW/cm2 range. The model was used based on the tunneling absorption under the irradiation by high-intensity ultrashort pulses in terms of the theory of ionization of solid in a field of strong electromagnetic wave. The effect of the energy gap of material on the threshold of laser ablation was adequately explained.

The tricritical point of a ferroelectric semiconductor in the field of strong electromagnetic wave

Abstract Within a two-band model of narrow-gap semiconductor, the interaction between electrons and transverse optical (TO) phonons is considered in the field of strong electromagnetic wave. The temperature of the structural phase transition due to TO-mode condensation with q = 0 is found to decrease in the field of the wave. Increase in the energy of direct optical interband dipole transition λ produces a change in the kind of the phase transition, so that a tricritical point appears in the phase diagram with variables (T, λ). The critical field intensity of the wave is found to be 106V/cm in the case of SnTe.