Angular feature of conical emission in an isotropic amorphous medium pumped by femtosecond pulses

Abstract

Broadband parametric upconverted conical emission (CE) has been investigated in an isotropic amorphous medium pumped by femtosecond laser pulses, which covers a broad range from 470 to 630 nm. Three theoretical models were analyzed to interpret the angular beam of CE. The CE spectra and their angular positions have been experimentally measured, which can be explained well by nonlinear X-wave model and Cerenkov type phase matching model rather than four-wave mixing (FWM) model.