AVS 60th International Symposium and Exhibition
    MEMS and NEMS Monday Sessions
       Session MN+NS-MoA

Paper MN+NS-MoA3
Multiplexed Nanomechanical Devices with Single Wavelength Nanophotonic Actuation and Detection

Monday, October 28, 2013, 2:40 pm, Room 102 A

Session: Optomechanics, Photonics, and Quantum Nanosystems
Presenter: V.T.K. Sauer, University of Alberta and The National Institute for Nanotechnology, Canada
Authors: V.T.K. Sauer, University of Alberta and The National Institute for Nanotechnology, Canada
Z. Diao, University of Alberta and The National Institute for Nanotechnology, Canada
M.R. Freeman, University of Alberta and The National Institute for Nanotechnology, Canada
W.K. Hiebert, University of Alberta and The National Institute for Nanotechnology, Canada
Correspondent: Click to Email
Nano-optomechanical system (NOMS) devices offer great opportunity for use in on-chip inertial based mass sensing. They have demonstrated large displacement sensitivity, and their large operational bandwidth allows for very high frequency measurements. These properties are conducive to the transduction of very small nanomechanical resonator motion, and smaller nanomechanical resonators allow for smaller detectable masses. The ultimate goal is to create on-chip sensors that are as sensitive as time-of-flight mass spectrometers. Integrated NOMS systems see a nanomechanical structure modulate the optical properties of a nanophotonic device. This is detected with very high sensitivity by a single probe beam travelling along an integrated nanophotonic waveguide. Optical systems are advantageous in detecting multiplexed arrays of devices due to the reduced complexity of integration. Unlike electrical devices, multiple devices can be probed using a single input and output. This is done by designing the devices to respond to different wavelengths through isolated optical cavities. As a result, multiple signals can be sent along the same waveguide at different wavelength channels to reduce the overall complexity of the design. Here, a multiplexed system is investigated where cantilever and doubly clamped beam nanomechanical resonators are detected using racetrack resonator optical cavities. These devices can also be optically pumped using a modulated laser power in the waveguide which modulates the optical gradient force present on the nanomechanical beam. This is usually done at a wavelength different to the probe laser so the pump signal can be filtered prior to the photo detector. This dual laser pump/probe system can be simplified further using a single beam to act simultaneously as both the pump and probe. Here, the probe laser itself is modulated in power to pump the mechanical motion of the beam. This acts as a homodyne system where the modulated probe power is mixed with the signal created by the nanomechanical beam’s motion. This would further simplify implementation of a multiplexed nanomechanical resonator system due reducing the number of input signals. This homodyne signal is implemented in a phase locked loop using a lock-in amplifier, and the frequency stability is tracked to estimate the mass sensitivity of a single beam driven and detected device.