Colloidal optical waveguides structured by light

We present experimental study where we employed two counter-propagating Gaussian and elliptical Gaussian beams to self-arrange of microscopic polystyrene particles into single and several parallel linear structures, respectively. We investigated optical bound between the particles following their mutual separations. Such optically bound structures can be understood as colloidal waveguides whose self-focus incoming light and thus a cooling of thermal motion of optically trapped particles could be observed with increasing number self-arranged particles. In the case of two parallel colloidal waveguides we also observed that a distance between them decreases with increasing number of self-arranged particles. Our experimental observations were supported by theoretical model.