Abstract. The influence of spatial energy distribution in femtosecond laser beams on filamentary propagation in Ar and on evolution of the temporal shape and phases of the outgoing pulses were investigated. Beams with increased symmetry demonstrate more efficient energy coupling in the filament supporting development of a negative spectral chirp and producing broader spectra with a clear expressed shift towards shorter wavelengths. It is shown for the first time that modification of the spatial beam profile can perform fine control of compression dynamics resulting in spectral phase adjustment of the output pulses approaching the optimum for a given experimental configuration. As a demonstration, compression of initially 45 fs pulses down to 8.2 fs in a single-stage filamentation is provided.

Keywords: pulse compression

Print publication: Issue 12 (December 2009)
Received 6 May 2009, accepted for publication 30 July 2009
Published 21 September 2009