Numerical calculation of interparticle forces arising in association with holographic assembly

Recent advances in dynamic holography have resulted in spatial light modulators capable of producing an almost limitless variety of field distributions from a single incident beam. Holographic assembly is a technique that exploits this capability to generate and control multiple foci that can be used to trap and manipulate nanoparticles. Although the forces associated with conventional optical tweezers are well understood, the effects arising from the more complicated interactions associated with holographic assembly are not. We present a general and flexible method, based on T matrix theory, for investigating these effects and use it to calculate the forces between particles in a variety of optical environments.