Construction of multi-beam optical tweezers and studies of polarization-dependent interactions between optically trapped particles

This project built on my previous undergraduate research experience, where I studied the dynamics of an aerosol droplet optically trapped in air. Our goal was to investigate polarization-dependent interactions and self-organizing dynamic behavior of optically trapped microscopic particles in a colloidal suspension.

I constructed a custom microscope to realize a multi-beam optical tweezers capable of manipulating polystyrene microspheres in an aqueous solution. Several configurations were explored, including one with three independently steerable beams, two of which were electronically controllable with fast-steering gimbal mirrors. The frequency and angle of the fast-steering mirrors could be modulated independently along two orthogonal axes in order to create dynamic optical potentials in a variety of shapes, such as lines or circles.

I also set up a Kohler illumination system and calibrated a pattern recognition software to enable tracking of the individual spheres.