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Laser ablation experiments were undertaken on aluminum and silicon using ultrashort laser pulses.

A convenient method is described for optical characterization of thin films during growth. The method has been demonstrated on lead zirconate titanate (PZT) films deposited by pulsed laser ablation for various temperatures. The optical constants of the PZT films as well as the film growth rate were determined in situ by fitting (with three free parameters) the calculated reflectance as a function of film thickness to the experimental reflectance curve as a function of deposition time, as obtained by unpolarized laser reflectometry. The fitted parameters are the uniform complex PZT refractive index and the layer thickness (assumed proportional to time), with the complex refractive index of the platinum substrate being measured previously. These results compare well with the subsequent ellipsometric measurements made to assess the precision of the reflectomerry technique. Key words: Laser reflectometry, refractive index, in situ material characterization.

The high-frequency ultrasound generated by single laser pulses in thin (50 mum) aluminum foils as a function of the laser fluence is studied. The laser-pulse durations of 80 femtosecond and 270 picosecond were used to compare the ultrasound generated in two very different regimes, thermoelastic and ablation.

Studies the propagation of high-power short-pulse laser beams over considerable distances in air. Lateral dimensions of the filaments; Early values of plasma electron density; Use of longitudinal spectral interferometry.

Studies self-focusing and filamentation of electromagnetic beams in plasmas. Application of the nonlinear Schrodinger equation with saturating nonlinearities; Breaking up of sufficiently large isolated high-power beams with noticeable structure into numerous filaments; Estimation of the filament density in terms of the average intensity.

Studies the dynamics of a relativistic plasma wave (RPW) resonantly excited by a two frequency carbon dioxide laser pulse and the effects of this wave on a co-propagating relativistic electron beam. Resolution of the amplitude of the RPW and its harmonics in time and space with a Thomson scattering diagnostic.

Studies the influence of spherical geometry on nonlocal radial electron heat transport using perturbation analysis. Nonlocal expression for the radial flux obtained in the limit of large ion charge; Deviation of the spherical nonlocal heat transport from the planar theory.

Studies the high-frequency beatwave experiment and Manley-Rowe action evolution in a finite causal system. Eulerian Hilbert-Vlasov (HV) code for a realistically high ratio of driver frequency to plasma wave frequency; Striking features that have emerged from the HV simulations; Spatially integrated action transfer generalized to the case of a finite causal system.

Discusses the kinetic theory of ion-acoustic waves in hydrocarbon (CH) and two-ion-species plasmas. Mode frequencies; Landau damping; Numerical solution of the kinetic dispersion relation; Expansions of the kinetic dispersion relation and from fluid models; Ponderomotive response of the CH plasma.

Presents measurements of electron heat transport with non-Maxwellian (flattopped) distributions due to inverse bremsstrahlung absorption of intense microwaves in the University of California at Davis Aurora II device. Dominance of charged particle collisions in the afterglow plasma; Relaxation of the heat front after the microwave pulse.