title: Characterization of radiation pressure and thermal effects in a nanoscale optomechanical cavity.
abstract: Optical forces in guided-wave nanostructures have recently been proposed as an effective means of mechanically actuating and tuning optical components. In this work, we study the properties of a photonic crystal optomechanical cavity consisting of a pair of patterned Si3N4 nanobeams. Internal stresses in the stoichiometric Si3N4 thin-film are used to produce inter-beam slot-gaps ranging from 560-40 nm. A general pump-probe measurement scheme is described which determines, self-consistently, the contributions of thermo-mechanical, thermo-optic, and radiation pressure effects. For devices with 40 nm slot-gap, the optical gradient force is measured to be 134 fN per cavity photon for the strongly coupled symmetric cavity supermode, producing a static cavity tuning greater than five times that of either the parasitic thermo-mechanical or thermo-optic effects.
authors.affiliation: Thomas J. Watson, Sr., Laboratory of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Camacho
authors.forename: Jasper
authors.initials: J
authors.lastname: Chan
authors.forename: Matt
authors.initials: M
authors.lastname: Eichenfield
authors.forename: Oskar
authors.initials: O
authors.lastname: Painter