Dynamics of Laser-Induced 3D Microbubbles in an Absorbing Liquid

Date of Award


Degree Name

M.S. in Electro-Optics


Department of Electro-Optics


Advisor: Partha Banerjee


Optical trapping and manipulation of such microbubbles in a liquid can be used in precise drug delivery and other biological applications. In this work, the generation and subsequent dynamics of a microbubble in a liquid are investigated, both experimentally and theoretically. When a laser beam is focused into an absorbing liquid comprising colloidal red dye particles in isopropanol alcohol inside a thick quartz cuvette, microbubbles can be generated at around the focus due to nucleation and thermal cavitation. It is experimentally shown that in some cases, the generated microbubble initially moves away from the focus due to the longitudinal optical gradient force, and is later attracted towards the focus due to the longitudinal thermo-capillary force. The thermo-capillary force on the microbubble is determined by solving the heat equation using Fourier transform methods. When developing the complete force model in microbubble dynamics, the thermo-capillary force, optical force, buoyancy force, gravity, and the viscous force have been considered.



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