The Computer Generation of Holographic Optical Tweezers

Due to their ability to apply forces on a small scale, optical tweezers are useful for a variety of biological and physical applications. The utility of optical tweezers can be extended by producing multiple traps with different characteristics from a single beam. One method for achieving this is to manipulate the phase of a trapping laser's wave front with a computer generated kinoform displayed on a spatial light modulator. We compare the performance of two algorithms for kinoform calculation, a Gerchberg-Saxton algorithm and a direct search algorithm, and discuss how they address problems inherent to computer generated holographic optical tweezing.