Femtosecond supercontinuum generation in scattering media

Abstract

We report our results on the effect of random multiple scattering on the supercontinuum (SC) generation by intense light pulses. Spectral measurements are performed on the SC generated when femtosecond laser pulses propagate in water containing randomly suspended microspheres. We observed that the SC emission in the presence of scatterers is significantly suppressed in the blue side of the spectrum in comparison to that observed in neat water. We attribute this to the dissipation of incident energy, strong scattering of the shorter wavelengths, and stretching of the pulse temporally. This reasoning is supported by our experiments in neat water where we alter the shape of the incident femtosecond pulse by means of an acousto-optic programmable dispersive filter and find similar suppression in the blue side with the lengthening of the input pulse. We believe our study will help in understanding the physics governing applications that involve the transmission of high-intensity ultrashort pulses through long distances in scattering media like the atmosphere and seawater.