title: Ultrastable measurement platform: sub-nm drift over hours in 3D at room temperature.
abstract: Advanced optical traps can probe single molecules with Ångstrom-scale precision, but drift limits the utility of these instruments. To achieve Å-scale stability, a differential measurement scheme between a pair of laser foci was introduced that substantially exceeds the inherent mechanical stability of various types of microscopes at room temperature. By using lock-in detection to measure both lasers with a single quadrant photodiode, we enhanced the differential stability of this optical reference frame and thereby stabilized an optical-trapping microscope to 0.2 Å laterally over 100 s based on the Allan deviation. In three dimensions, we achieved stabilities of 1 Å over 1,000 s and 1 nm over 15 h. This stability was complemented by high measurement bandwidth (100 kHz). Overall, our compact back-scattered detection enables an ultrastable measurement platform compatible with optical traps, atomic force microscopy, and optical microscopy, including super-resolution techniques.
authors.forename: Robert
authors.initials: R
authors.lastname: Walder
authors.forename: D Hern
authors.initials: DH
authors.lastname: Paik
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Bull
authors.forename: Carl
authors.initials: C
authors.lastname: Sauer
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Perkins