Manipulation of microparticles using combined optical traps

Optothermal traps including vortex ones, have been implemented to capture and manipulate transparent and absorbing micro-objects. The current study deals with latex microspheres of various diameters and silver microparticles. The temperature gradient and corresponding convection fluxes of the liquid were formed by using a light filter absorbing at a wavelength of 0.53 μm as the bottom of the cell with the samples. Special phase masks were designed to form an optothermal trap of the Archimedes spiral shape. We have demonstrated the motion of microparticles along the Archimedes spiral in combined vortex trap caused by the transfer of an angular momentum.