Abstract

Laser pulses with high intensity (up to 10¹⁹ W/cm²) and ultrashort pulse duration (as short as 100 fs) were focused in dense gases and on solid samples. In gases, results include nonlinear refractive effects that cause the laser to remain collimated over distances longer than the confocal parameter, highly ionized material with relatively cold electrons, the emission of harmonics of the laser wavelength from both atomic nonlinearities and relativistic electron motion, electron-ion recombination radiation, intense Raman-scattered light from collective plasma effects, and far-infrared radiation from collectively accelerated electrons. In solids, results include· highly-ionized and dense material, hot elections and the emission of short-pulse soft and hard x-rays, and far infrared radiation.

© 1993 Optical Society of America