Abstract

We consider nonlinear light propagation in colloidal suspensions of spherical dielectric nanoparticles. When an optical beam passes through a colloidal medium composed of dieletric particles in a solvent, the optical gradient force acts against particle diffusion, increasing the refractive index in regions of higher light intensity, see Fig. 1(a). The corresponding local refractive index change is of self-focusing type and allows for creation of spatial optical solitons [1]. Recently, it was shown theoretically [2] that the optical response of a colloidal medium in the hard- sphere approximation can lead to optical bistability and the existence of two stable soliton solutions for the same beam power, i. e. the soliton bistability of the first kind [3, 4]. This opens novel opportunities for the control of the soliton beams via their collision and switching.

© 2009 IEEE