In light absorbing liquids optical trapping of solid micro-objects but also gas bubbles can be achieved and explained bythe mechanisms involving the hydrodynamic whirls formation. The various forms of these whirls, that arise due tooptothermal Marangoni effect induced by laser light beam, are able to accelerate the objects movement, transport themand subsequently trap at the laser beam center but also close to it. The usual light gradient field force and scattering forcesolely are insufficient and even not adequate to properly describe the mentioned by us particle trapping effects as the trappotential extends to much larger distances that the beam waist. We will demonstrate the mechanism of optical trappingand transporting of gas bubbles and will discuss the physics of whirls formation in this case. The numerical modelling ofMarangoni flows at the liquid-gas interface confirms the experimental findings. We also demonstrate a novel type oftrapping of micro-objects that occurs inside a toroidal whirl induced by laser in dye-doped oil. This type of trapping isquite unusual but allows to transport objects immobilized far from the beam waist just avoiding their excessive heating.
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