AUTHOR=Muñoz-Pérez F. M. , Ortega-Mendoza J. G. , Padilla-Vivanco A. , Toxqui-Quitl C. , Sarabia-Alonso J. A. , Ramos-García R. 

TITLE=Steady-State 3D Trapping and Manipulation of Microbubbles Using Thermocapillary

JOURNAL=Frontiers in Physics

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.585590

DOI=10.3389/fphy.2020.585590

ISSN=2296-424X

ABSTRACT=<p>An experimental and theoretical study on the 3D trapping and manipulation of microbubbles by means low power laser-induced temperature gradients induced in ethanol by bulk light absorption (<italic>λ</italic> = 1550 nm) is presented. Two optical fibers were used: One for bubble generation (OF<sub>G</sub>) and the other for both trapping and manipulation (OF<sub>T</sub>). Light from a Q-switched pulsed laser (<italic>λ</italic> = 532 nm and pulse width <italic>τ</italic><sub>p</sub> = 5 ns) propagates in fiber OF<sub>G</sub> and gets absorbed at silver nanoparticles (AgNPs), previously photodeposited, at the distal end of a fiber optic core, generating the microbubbles. In the fiber OF<sub>T</sub>, light of low power CW laser was used to trap and manipulate the bubbles by thermocapillary induced by light bulk absorption in ethanol. The microbubble generated on OF<sub>G</sub> migrates toward the fiber OF<sub>T</sub>. The equilibrium between the buoyancy force <italic>F</italic><sub><italic>B</italic></sub><italic>,</italic> drag force <italic>F</italic><sub><italic>D</italic></sub> and the Marangoni force (also known as thermocapillary force) <italic>F</italic><sub><italic>M</italic></sub> gives rise to a 3D stably trapping and manipulation of the microbubble for the best time to our best knowledge.</p>