Optical propulsion of microspheres along a channel waveguide produced by Cs⁺ ion-exchange in glass

Experimental results on optical propulsion of polystyrene microspheres are presented. Particles of 3, 7 and 10 µm diameter were stably guided on top of a waveguide. The waveguides were made by Cs+ ion-exchange in glass for singlemode operation at 1082 nm. The highest average velocity for single particles was about 33 µm/s, achieved for 10 µm diameter particles and a fibre output power of 870 mW. Particle velocity was measured as a function of the fibre output power for the three different particle sizes. Under the same input conditions, it was observed that collections of particles move faster than single particles and that the velocity increases with particle size. The formation of several hundred micrometer long chains of particles and some evidence of particle binding is reported