A microchip optomechanical accelerometer

• Published in: arXiv.org
• Main Authors: Krause, Alexander G, Winger, Martin, Blasius, Tim D, Lin, Qiang, Painter, Oskar
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 26.03.2012
• Subjects: Acceleration; Accelerometers; Broadband; Computer architecture; Cooling effects; Displacement measurement; Electromagnetic interference; Inertial navigation; Optics; Photonic crystals; Physics - Optics
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1203.5730

The monitoring of accelerations is essential for a variety of applications ranging from inertial navigation to consumer electronics. The basic operation principle of an accelerometer is to measure the displacement of a flexibly mounted test mass; sensitive displacement measurement can be realized using capacitive, piezo-electric, tunnel-current, or optical methods. While optical readout provides superior displacement resolution and resilience to electromagnetic interference, current optical accelerometers either do not allow for chip-scale integration or require bulky test masses. Here we demonstrate an optomechanical accelerometer that employs ultra-sensitive all-optical displacement read-out using a planar photonic crystal cavity monolithically integrated with a nano-tethered test mass of high mechanical Q-factor. This device architecture allows for full on-chip integration and achieves a broadband acceleration resolution of 10 \mu g/rt-Hz, a bandwidth greater than 20 kHz, and a dynamic range of 50 dB with sub-milliwatt optical power requirements. Moreover, the nano-gram test masses used here allow for optomechanical back-action in the form of cooling or the optical spring effect, setting the stage for a new class of motional sensors.