Dynamics of microbubble generation and trapping by self-focused femtosecond laser pulses

Different from conventional optical tweezers used for trapping high refractive index micron-sized particles, bubble generation and trapping by femtosecond laser offer a unique strategy to manipulate microbubbles. Using high frequency ultrasound imaging and fast-frame optical video microscopy, we obtained results revealing the spatiotemporal characteristics of bubble generation and trapping by self-focused femtosecond laser pulses at multiple locations along the laser beam. We detected distinct acoustic signals associated with the laser focus and measured the trapping force by using acoustic radiation force to detrap the bubble from the laser beam.