A method for generation of a chirped, ultrawideband infrared source by use of optical parametric generation in periodically poled crystals and pumped by a chirped Ti:sapphire laser is described. A similar to35% bandwidth in the idler branch was demonstrated in a periodically poled LiTaO3 crystal pumped by a chirped Ti:sapphire laser with 2.1% bandwidth. Optical parametric generation and optical parametric amplification configuration allowed us to generate up to a similar to250-muJ chirped pulse from 2.1 to 3 mum. (C) 2005 Optical Society of America.

The autoresonance phenomenon allows excitation of a classical, oscillatory nonlinear system to high energies by using a weak, chirped frequency forcing. Ladder climbing is its counterpart in quantum mechanics. Here, for the first time to our knowledge, conditions for the transition from the quantum to the classical regimes are outlined. The similarities and differences between the two approaches are presented.

Generation of axisymmetric stable, long plasma channels with temperatures of 8 eV and electron densities ∼ 10[sup 19] cm[sup -3] by a high-current evaporating-wall capillary discharge with prepulse ablative plasma is reported. Results of spectroscopic measurements of the temperature and electron density of plasma produced in a polyethylene capillary are presented. The discharge provides a convenient source of dense highly ionized plasmas for laser-plasma interaction studies. [ABSTRACT FROM AUTHOR]

A method to generate chirped ultrawide-band sources with a chirp bandwidth of about 50% in the infrared is described and experimentally verified. It is based on optical parametric generation in periodically poled crystals with a chirped Ti:sapphire as a pump source. We have demonstrated a 27% wide bandwidth in the signal branch and 45% bandwidth in the idler branch when a periodically poled KTP crystal was pumped by a chirped Ti:sapphire laser with 12 nm full width at half maximum bandwidth. © 2003 American Institute of Physics.

An experimental study of third-harmonic generation in methane with a 100-fs, 820-nm, Ti:sapphire laser in a tight focusing geometry is presented. The harmonic intensity and bandwidth were measured in a range of intensities extending from below to far above the first ionization threshold and at pressures as high as 10 atm (1 atm = 760 Torr). The harmonic signal follows a power-law dependence on laser intensity with an exponent of similar to 7 and saturates at an intensity I-s similar to 4 x 10(14) W/cm(2). The conversion efficiency was found to increase with the pressure for laser intensities smaller than the saturation intensity I-s and to decrease with the pressure at larger intensities. At laser intensities larger than the saturation intensity a substantial modification in the third-harmonic bandwidth and structure was observed. (C) 1999 Optical Society of America [S0740-3224(99)00905-4].