Abstract
Microbubbles were trapped below a solid boundary using the laser trapping technique. We measured the trapping forces acting on the bubble both in the vertical and lateral directions. The trapping forces were almost the same as those measured for the bubbles trapped below the free surface. We succeeded in manipulating the trapped bubbles in the vertical direction near the solid boundary. We also simulated the bubble trajectories when the bubbles escaped from the trapping region under shear flows.
