Abstract
We investigated the injection of microbubbles through a micro capillary tube. The number density of the injected microbubbles was controlled with an actuator. These microbubbles are planed to be used for the laser trap or laser manipulation of microbubbles. In the laser trap, we use the laser cone that is made by rotating the laser ring. We succeeded in injecting microbubbles with the velocity of about 150μm/s. We simulated the trajectory of microbubbles injected through the capillary tube until they trapped by the laser cone. The optical force, buoyancy and viscous drag force were taken into account in the simulations. The simulations showed that the microbubble of 5μm diameter, which was injected near the axis of the laser cone, was trapped below the focus of the laser beam if the velocity of bubble injection was slower than about 500μm/s.
