Some consequences during the propagation of an intense femtosecond laser pulse in transparent optical media: a strongly deformed white-light laser

We present some results concerning the propagation of intense femtosecond T i:sapphire laser pulses in matter and especially in air. We show that the s upercontinuum created during the propagation preserves the spectral coheren ce of the initial pulse and both together form a chirped-white-light laser. Furthermore, we detected the photoemission of N-2 and N-2(+) to measure th e intensity dependence of a focused laser pulse in air along the propagatio n distance and we observed a multiple refocusing. Finally, we underlined a clear charge separation in the plasma created a focused pulse in air giving rise to a short electric pulse.