Increasing Trap Stiffness with Position Clamping in Holographic Optical Tweezers
Published by the Optical Society of America Optics Express Vol. 17, Issue 25, pp. 22718-22725 (2009) https://doi.org/10.1364/OE.17.022718
We present a holographic optical tweezers system capable of position clamping multiple particles. Moving an optical trap in response to the trapped object’s motion is a powerful technique for optical control and force measurement. We have now realised this experimentally using a Boulder Nonlinear Systems Spatial Light Modulator (SLM) with a refresh rate of 203Hz. We obtain a reduction of 44% in the variance of the bead’s position, corresponding to an increase in effective trap stiffness of 77%. This reduction relies on the generation of holograms at high speed. We present software capable of calculating holograms in under 1ms using a graphics processor unit.