title: Stimulated Raman X waves in ultrashort optical pulse filamentation.
abstract: We demonstrate that ultrashort pulse filamentation in liquids with strong Raman gain leads to the spontaneous formation of nonlinear X waves at a Raman-shifted wavelength. We measured as much as 75% energy conversion efficiency into a Raman X wave in ethanol starting from 1 ps pulses due to the group velocity matching between the pump and Raman X pulses. Large Raman gain of a weak seed signal was observed in water, associated with a strong spatiotemporal transformation of the seed into an X wave.
authors.affiliation: Consorzio Nazionale Interuniversitaro per le Scienze della Materia, Como, Italy. daniele.faccio@uninsubria.it
authors.forename: Daniele
authors.initials: D
authors.lastname: Faccio
authors.forename: Alessandro
authors.initials: A
authors.lastname: Averchi
authors.forename: Audrius
authors.initials: A
authors.lastname: Dubietis
authors.forename: Paolo
authors.initials: P
authors.lastname: Polesana
authors.forename: Algis
authors.initials: A
authors.lastname: Piskarskas
authors.forename: Paolo
authors.initials: P
authors.lastname: Di Trapani
authors.forename: Arnaud
authors.initials: A
authors.lastname: Couairon