Single and Parallel Microfluidic Actuation for Mesoscale Objects Manipulation Using Benard-Marangoni Convection

In this paper, we present the non-contact manipulation of mesoscale random-shaped, large and heavy objects immersed in thin liquid water layers (< 0.6 mm). The thin layers are open to the air. The manipulation principle used is Benard-Marangoni convection using infra red laser (1480 nm) absorption. Laser absorption generates surface-tension-driven flows. We use these flows to drag immersed objects toward the laser focus. High speed flows can be reached; therefore high speed object manipulation can be achieved (several mm/s). Experimental measurements show a velocity of about 6 mm/s for a spherical glass bead of 240 mu m in diameter. With these flows, forces much larger than optical tweezers can be obtained.