We present the generation and 3D manipulation of microbubbles by thermal gradients, induced by low powernanosecond pulsed laser in non-absorbent liquids. Light absorption at photodeposited silver nanoparticles on theoptical fiber tip heat up the surrounding liquid, which leads to optothermal effects. With each laser pulse amicrobubble is detached from the optical fiber end, creating a microbubbles-stream. The microbubbles move awayfrom the optical fiber end driven by non-spherical cavitation until they coalesce creating a main-bubble which isattracted towards the optical fiber end by Marangoni force. In addition, the main-bubbles are under the influence ofbuoyancy and gravity forces, which act upwards and downwards, respectively. The balance of these forces allows the3D manipulation of the main-bubble. The main-bubble position can be controlled by careful control of the pulseenergy. To our knowledge this is the first time that 3D manipulation of microbubbles using pulsed lasers isdemonstrated.
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