Intensity Spikes in Laser Filamentation: Diagnostics and Application

Mette B. Gaarde, Louisiana State University
Arnaud Couairon, Centre de Physique Theorique de l' Ecole Polytechnique


We present calculations with subcycle precision of laser-driven filamentation in argon which show that the laser peak intensity can exceed the clamping intensity by a factor of 3 during recurring spikes which can last over several centimeters of propagation. The high intensity occurs during a few-femtosecond subpulse in the trailing edge of the main pulse and gives rise to isolated 500 attosecond, 2 pJ pulses which can be extracted from the filament. We also show that the high harmonic radiation emerging from the filament is an excellent diagnostic of the intensity spikes. © 2009 The American Physical Society.