Holographic beam forming to generate and control multiple optical traps has proved successful using high-resolution spatial light modulators (SLMs). This type of beam control allows a multitude of traps to be independently controlled in three dimensions. Also, exotic beam shapes and profiles can be generated, which gives the optical trapping system even greater flexibility. Until recently, the generation of high resolution phase patterns has limited the speed of dynamic holographic optical trapping (HOT) systems. Today, video rate operation controlling hundreds of traps using 512x512 phase masks is possible and significantly faster operation is possible with fewer traps using less phase resolution. Therefore, phase-only liquid crystal modulator response is becoming the bottleneck. This paper discusses recent advances in SLM developments which address this issue.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.