Towards Sub-Nanometer Resolution Optical Tweezers

Optical tweezers with sub-nanometer resolution can provide new insights into how nucleic-acid associated molecular motors work, since elementary steps of one base-pair or less can be resolved. For example, elementary 0.34 nm steps of RNA-Polymerase, as well as of a viral packaging motor, have been observed with high-resolution optical tweezers instruments. Techniques for achieving ultra-stable trapping/microscopy include housing the instrument in a Helium atmosphere, temperature control, and stabilizing laser-pointing and intensity.We present results on optimizing the spatial resolution of our optical tweezers instrument, including experiments with a Helium atmosphere, fiber-coupled actively stabilized detection lasers, and precise temperature control of the trapping objective.