Experimental investigations of three laser-induced synchronized bubbles

Abstract

Herein, we investigated experimentally the dynamics of three laser-induced, same-sized, symmetrically aligned, and synchronized bubbles. Three synchronized laser beams split from the same beam using a Diffractive Optical Element splitter were focused on water, and then we obtained three bubbles. Another nanosecond laser pulse was used to probe the bubbles to obtain shadowgraphs. The exact delay of the excited and detected light was controlled using a delay generator. The results revealed that the maximum volumes of bubbles in arrays decrease as the normalized distance falls, while the lifetimes and translation increase. It was explained by the interaction between the acoustic radiation of bubbles and the surrounding bubbles. The shrinkage of linear bubble arrays exists an anomaly. The center bubbles were stretched, to ellipsoid, stick, even fractured, by the peripheral bubbles. The closer they are, the more distinct is the above phenomenon. However, when the normalized distance was sufficiently small, instead of being stretched, the center bubbles were compressed to disk shape and thus shrank with the whole array. Finally, the dependence of the distance on the energy transfer of the bubble system is also discussed.