Laser-driven viscous micropump using a spining rotor

Optically driven micropumps using viscous drag exerted on a rotating microrotor was developed. As the first prototype, a disk microrotor (diameter: 10 mum), which has three columns as targets for the optical trap, is confined to a U-shaped microchannel. To pump fluid, the disk microrotor is rotated by a time-shared optical trapping technique. The flow field inside the U-shaped microchannel was analyzed using finite element method (FEM) based on the Navier-Stokes equation. The optimized micropump was fabricated using a two-photon microfabrication technique. The flow rate of the micropump agreed with simulation result obtained by FEM analysis. Furthermore, we developed a helical rotor as a spining rotor inside the U-shaped microchannel. Unlike the previous disk microrotor, the helical rotor can be rotated just by focusing a laser beam without scanning of the laser beam. It was demonstrated that the rotation of the helical rotor generated fluid flow.