Abstract

Fundamental understanding of high intensity ultrashort laser pulse propagation through media is critical to applications such as harmonic generation and development of recombination type, xuv/x-ray lasers driven by optical field ionization. At relativistic intensities self-induced channeling or waveguiding effects have been predicted for cases of nonionizing or preformed plasma media ¹. For many single pulse propagation experiments optical field ionization rapidly forms an ionization front at the leading edge of the pulse envelope traveling at relativistic speeds. It is important to understand formation mechasisms of this front and its effects on propagation of intense laser pulses. Strong field ionization can occur at rates exceeding the laser frequency. Such abrupt alteration of the propagation constant results in significant reduction of transmitted pulse energy on axis and in predominantly 'blue biased' shifts in the incident pulse spectrum².

© 1994 Optical Society of America