Multidimensional optomechanical cantilevers for high-frequency force sensing

Abstract

High-frequency atomic force microscopy has enabled extraordinary new science through large bandwidth, high-speed measurements of atomic and molecular structures. However, traditional optical detection schemes restrict the dimensions, and therefore the frequency, of the cantilever—ultimately setting a limit to the time resolution of experiments. Here we demonstrate optomechanical detection of low-mass, high-frequency nanomechanical cantilevers (up to 20 MHz) and anticipate their use for single-molecule force measurements. These cantilevers achieve 2 fm ${\text{Hz}^{-1/2}}$ displacement noise floors, and force sensitivity down to 132 aN ${\text{Hz}^{-1/2}}$ . Furthermore, the ability to resolve both in-plane and out-of-plane motion of our cantilevers makes them excellent candidates for ultrasensitive multidimensional force spectroscopy, and optomechanical interactions, such as tuning of the cantilever frequency in situ , provide opportunities in high-speed, high-resolution experiments.

Keywords

• optomechanics
• atomic force microscope
• cantilever
• nanomechanical
• whispering gallery mode resonators
• 07.79.Lh