LASER-INDUCED FORCE FOR BUBBLE-TRAPPING IN LIQUIDS

The laser-induced thermal force that traps a bubble in an absorbing li quid is studied theoretically and experimentally. The force origins fr om the thermal gradients of the surface tension induced by a laser bea m over the bubble surface. It is shown that this force is proportional to the square of the bubble radius and to the thermal gradient of the surface tension. A simple experimental method based on comparison wit h the Archimedes' flotation force, is used for the measurement of this force. The experimental results, performed on ethanol solutions of io dine, confirm the theoretical predictions.