A viscous micropump using a spinning microrotor driven by a Laguerre-Gaussian beam

We proposed a novel viscous micropump driven by a Laguerre-Gaussian beam (LG beam). The micropump consists of a U-shaped microchannel and a microrotor. In this micropump, the rotation of the microrotor enables to transport fluid by use of the viscous drag surrounding the microrotor. To rotate the microrotor, we developed an optical manipulation system using a LG beam. Since LG beam has orbital angular momentum, it enables to rotate multiple microparticles along its doughnut-ring-like transversal intensity distribution. We examined the dependence of the rotation of multiple microparticles on topological charge l of LG beam. In our preliminary experiments, the highest rotation speed of 240 rpm with a rotation radius of 7.5 µm was obtained with a LG beam with topological charge l = 16. According to the result, we designed and fabricated LG beam driven microrotors of radius of 7.5 µm by using two-photon microfabrication. By optimizing the thickness of the microrotor, a microrotor driven at 240 rpm was produced by two-photon microfabrication. Finally, viscous micropump using the high-speed microrotor was developed.