We have experimentally observed the trapping of a gas bubble in water by focused laser radiation. The optical trap was provided by 200-fs pulses of a Ti-sapphire laser operating at a repetition rate of 100 kHz. The laser radiation was focused in water by an objective with a numerical aperture of 0.5. The trapping force in water is estimated as ∼200 pN at an average laser power of 20 mW, which is by two orders of magnitude greater than the efficiency of a traditional laser tweezers. The trapping force arises upon local heating of gas inside a bubble due to nonlinear absorption in the focal region.
DOI
No comments:
Post a Comment