A high-resolution microchip optomechanical accelerometer

By Alexander G. Krause, M. Winger, T. Blasius, Qiang Lin, Oskar J. Painter. Nature Photonics, 2012

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The monitoring of acceleration is essential for a variety of applications ranging from inertial navigation to consumer electronics1,2. Typical accelerometer operation involves the sensitive displacement measurement of a flexibly mounted test mass, which can be realized using capacitive3,4, piezo-electric5, tunnel-current6,7 or optical8,9,10,11 methods. Although optical detection provides superior displacement resolution8, resilience to electromagnetic interference and long-range readout7, current optical accelerometers either do not allow for chip-scale integration or utilize relatively bulky test mass sensors of low bandwidth8,9,10. Here, we demonstrate an optomechanical accelerometer that makes use of ultrasensitive displacement readout using a photonic-crystal nanocavity12 monolithically integrated with a nanotethered test mass of high mechanical Q-factor13. This device achieves an acceleration resolution of 10 µg Hz−1/2 with submilliwatt optical power, bandwidth greater than 20 kHz and a dynamic range of greater than 40 dB. Moreover, the nanogram test masses used here allow for strong optomechanical backaction14,15,16,17, setting the stage for a new class of motional sensors. Researchers demonstrate a chip-scale optomechanical accelerometer with displacement read-out using a photonic crystal cavity integrated with a tethered nanogram test mass of high mechanical Q-factor. The device achieves an acceleration resolution of 10 µg Hz−1/2 for sub-mW optical power, a bandwidth greater than 20 kHz, and a dynamic range of 50 dB.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/91a7b7ff0cf3d7b0986e073fcad9e00f3de113fe