12 February 2007 All-optical micromechanical chemical sensors
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We describe experimental results from micromechanical resonators coated with chemoselective polymers that detect chemical vapors from volatile organic compounds or explosives using all-optical interrogation. The shift in the resonant frequency of a gold microbeam is read-out using photothermal actuation and microcavity interferometry. For detection of toluene vapor, response times of less than 5 seconds are achieved for vapor concentrations as low as 60 ppm. For detection of TNT vapor, concentrations as low as 10 ppb are detected in 100 seconds. An analysis of the measured frequency noise in these sensors shows that it is dominated by thermal-mechanical fluctuations at the fundamental flexural mode. Our measurements thus indicate that thermal-mechanical frequency noise is the primary intrinsic detection limit for typical resonant-frequency MEMS biosensors or chemical vapor sensors.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Todd H. Stievater, Todd H. Stievater, William S. Rabinovich, William S. Rabinovich, Mike S. Ferraro, Mike S. Ferraro, J. Brad Boos, J. Brad Boos, Nicolas A. Papanicolaou, Nicolas A. Papanicolaou, Jennifer L. Stepnowski, Jennifer L. Stepnowski, R. Andrew McGill, R. Andrew McGill, } "All-optical micromechanical chemical sensors", Proc. SPIE 6464, MEMS/MOEMS Components and Their Applications IV, 64640D (12 February 2007); doi: 10.1117/12.700224; https://doi.org/10.1117/12.700224

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