Generation of an extended quasirotational spectrum by self-focusing of picosecond pulses in compressed hydrogen

Self-focusing of λ = 1.06 μm radiation pulses of 30 ps duration in compressed hydrogen resulted in generation of an extended quasirotational anti-Stokes spectrum consisting of lines with a smooth spatial profile. An increase in the focal length of the lens, which focused the pump radiation in a cell, altered drastically the nature of the output radiation: a set of rings, corresponding to generation of a sequence of vibrational lines, was observed.