Multiple re-focusing of ultrashort laser pulse propagating in condensed matter

Abstract

We focused a 38 fs laser pulse, which is spatially filtered, into a glass cell containing a very dilute solution of coumarin 440 in methanol. Via three photons fluorescence of coumarin, up to 6 re-focusing filaments were observed along one straight line. This is the first evidence showing a way to control multiple filamentation.