We provide what is to our knowledge the first experimental evidence that multiple filamentation (MF) of ultrashort pulses can be induced by input beam ellipticity. Unlike noise-induced MF, which results in complete beam breakup, the MF pattern induced by small input beam ellipticity appears as a result of nucleation of annular rings surrounding the central filament. Moreover, our experiments show that input beam ellipticity can dominate the effect of noise (transverse modulational instability), giving rise to predictable and highly reproducible MF patterns. The results are explained with a theoretical model and simulations.
© 2004 Optical Society of America
Audrius Dubietis, Gintaras Tamošauskas, Gadi Fibich, and Boaz Ilan, "Multiple filamentation induced by input-beam ellipticity," Opt. Lett. 29, 1126-1128 (2004)