Hard x-ray radiation yield from a dense plasma as a function of the wavelength of the heating ultrashort laser pulse

The effect of intensity, length, and wavelength of an ultrashort laser puls e on the formation of a hot electron component in a dense laser-produced pl asma was first investigated in a single experiment. For a pulse length of 1 ps (or 200 fs, but with an energy contrast ratio of similar to 20), it was shown that the principal mechanism of generation of hot electrons is the r esonance absorption of laser radiation and that the temperature of hot elec trons depends on the laser pulse intensity I and the wavelength lambda as T -h similar to (I lambda(2))(1/3) The homogenisation of the nanostructures o f porous silicon due to a poor contrast ratio or a long duration (1 ps) of the laser pulse lowers the yield of hard x-ray radiation compared to the ca se of high-contrast 200-fs pulses.