Optical propulsion and sorting of microparticles on silicon nitride strip waveguides

This paper describes the direct implementation of the sorting of differently sized glass particles on the surface of silicon nitride strip waveguides due to different propulsion speeds that can be controlled by varying the optical input power. The high refractive index contrast (Δn ~0.52 as compared to silicon oxide) allows for strong light confinement in waveguides of sub-micron thickness (180nm). The use of a tapered fiber increases coupling efficiency and allows us to achieve a guided power of 24mW with 320mW of input power.