Optical properties measurement of a dielectrophoresis-driven liquid-core/liquid-cladding optical waveguide

In this paper, dielectrophoresis (DEP) and electrowetting-on-dielectric (EWOD) are used to generate a liquid-core/liquid-cladding optical waveguide. Different from continuously supplied core and cladding liquid in micromachined microchannel, EWOD creates a metered volume droplet which is later deformed by DEP to be the liquid core of the optical waveguide. Hence, the presented liquid-core/liquid-cladding optical waveguide is electrically tunable and programmable. The DEP-defined core liquid preserves the advantage of the smooth liquid-liquid interface, while the stationary core and cladding liquid would eliminate scattering losses caused by liquid flowing. Light transmission is achieved in the DEP-driven liquid-core/ liquid-cladding optical waveguide. The propagation loss is measured by observing the fluorescent change of 1 mM Rhodamine-dyed core liquid excited by a Nd-YAG II laser.