Stimulated Raman X waves in ultrashort optical pulse filamentation.
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.
Faccio
Daniele
D
Consorzio Nazionale Interuniversitaro per le Scienze della Materia, Como, Italy. daniele.faccio@uninsubria.it
Averchi
Alessandro
A
Dubietis
Audrius
A
Polesana
Paolo
P
Piskarskas
Algis
A
Di Trapani
Paolo
P
Couairon
Arnaud
A