Abstract

Spectral broadening of femtosecond pulses into a supercontinuum has been one of the most striking discoveries in modern day nonlinear optics [1]. It has enabled applications ranging from spectroscopy and metrology to telecommunication and medicine. Amongst the physical principles underlying supercontinuum generation the commonly used list includes a variety of four-wave mixing processes [2, 3], soliton fission [4], Raman induced soliton self-frequency shift, and dispersive wave generation mediated by solitons [4, 5]. Though all of the above effects contribute to supercontinuum generation none of them determines the final spectral width. In this work we argue that the most profound role in shaping the spectrum is played by the effect of radiation trapping by a gravity like potential created by accelerated solitons. The underlying physics of this effect has a straightforward analogy with the equivalence between the gravitational force and the inertial force acting on an observer moving with a constant acceleration.

© 2007 Optical Society of America