High harmonic generation and attosecond pulse production in dense medium

V. V. Strelkov, V. T. Platonenko, A. Becker, Alexander M. Sergeev
We have studied the high harmonic generation and attosecond pulse production in a plasma or gas under conditions when the single-atom response is affected by neighboring ions of the medium. We solve numerically the threedimensional Schrodinger equation for a single-electron atom in the combined fields of the parent ion, the neighboring particles and the laser, and average the results over different random positions of the particles using the Monte-Carlo method. We observe a change of the
more » ... hange of the harmonic properties due to a random variation of the harmonic phase induced by the field of the medium, when the medium density exceeds a certain transition density. The transition density is found to depend on the harmonic order, but it is almost independent of the fundamental intensity. It also differs for the shorter and longer quantum paths. The latter effect leads to a narrowing of the harmonic lines and a shortening of the attosecond pulses generated using a group of harmonics. The effect of the medium might be important even for much lower densities in the case ofXUV generation using radiation in the micron wavelength regime.
doi:10.1117/12.675492 fatcat:ic6jpt34z5fr5hxwjx2wbdixke