Optical trapping and manipulation of micro-particles using Laguerre-Gaussian beam and spiral beam pattern

Optical tweezers use strongly focused laser beams to trap and manipulate micro-particles. This is a direct consequence of high intensities and high intensity gradients generated by laser beams. In recent years there has been enormous amount of research and development for trapping and manipulation of particles using advanced beam shapes, which includes LaguerreGaussian (LG) beam and spatial beam patterns. The LG beam and spatial beam patterns were generated using beam-shaping optics and Mach-Zehnder based interferometer. The interference pattern involves the superposition of LG0 beam with spherical wave. We further demonstrate the rotation of the spiral pattern. A system has been developed to controllably rotate optically trapped objects in a spiral interference pattern. Objects are trapped in the spiral arms of the interference pattern and changing the optical path length of one of the interfering beams can rotate the whole pattern. Particles trapped in the beam follow the rotation of the pattern as they are continuously drawn into the region of highest light intensity of the moving interference pattern due to the gradient force of light.