Configurable Vibrational Coupling in Laser-Induced Microsecond Oscillations of Multi-Microbubble System

Abstract

We study the coupled vibrational dynamics of sub-MHz self-oscillating bubbles at separations of 14 to 92 {\mu}m. Two vapor-rich microbubbles are generated via photothermal heating; their interactions are captured in real space and time via a high-speed camera. By controlling the distance between bubbles with micrometer precision, we induce in- and anti-phase hybridized vibrations, with mode frequencies varying from 0.5 to 0.8 MHz. The observed coupled modes are reproduced by the extended Rayleigh-Plesset equation that takes pressure interactions between the bubbles into account. Our findings facilitate the optimization of bubble array positioning for spatio-temporal microfluidic control.