Conical continuum Stokes and anti-Stokes emissions are observed when intense 100-fs/620-nm ultrafast laser pulses propagate through an ethylene glycol medium. The angle of the anti-Stokes conical emission is modeled by class-II Raman and four-photon parametric generations in a small-scale filament with a nonlinear index change.
© 1993 Optical Society of America
Qirong Xing, Kwong Mow Yoo, and Robert R. Alfano, "Conical emission by four-photon parametric generation by using femtosecond laser pulses," Appl. Opt. 32, 2087-2089 (1993)