Propagation of intense ultrashort laser pulses in a plasma filled capillary tube: Simulations and experiments

Recent experiments [F. Dorchies , Phys. Rev. Lett. 82, 4655 (1999)] have de monstrated monomode guiding over 100 Rayleigh lengths (10 cm) of high inten sity, ultrashort laser pulses in a dielectric capillary tube filled with lo w pressure He gas. A model for the propagation of femtosecond laser pulses in a capillary tube, coupled with the tunnel ionization of the gas filling the capillary tube, is derived and solved numerically using the parameters of these experiments. The simulations accurately reproduce experimentally m easured damping lengths, transmitted pulse energy and spectrum at the outpu t of the capillary tube. They show that a few cm long, homogeneous, plasma column with an electron density of the order of 10(17) cm(-3) is created fo r an incident intensity of 4x10(15) W/cm(2). (C) 2001 American Institute of Physics.