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Mid-Infrared Fiber-Coupled Photoacoustic Sensor for Biomedical Applications
Institute for Quantum Electronics, ETH Zurich, Schafmattstrasse 16, 8093 Zurich, Switzerland
* Author to whom correspondence should be addressed.
Received: 29 October 2012; in revised form: 20 December 2012 / Accepted: 22 December 2012 / Published: 2 January 2013
Abstract: Biomedical devices employed in therapy, diagnostics and for self-monitoring often require a high degree of flexibility and compactness. Many near infrared (NIR) optical fiber-coupled systems meet these requirements and are employed on a daily basis. However, mid-infrared (MIR) fibers-based systems have not yet found their way to routine application in medicine. In this work we present the implementation of the first MIR fiber-coupled photoacoustic sensor for the investigation of condensed samples in the MIR fingerprint region. The light of an external-cavity quantum-cascade laser (1010–1095 cm-1) is delivered by a silver halide fiber, which is attached to the PA cell. The PA chamber is conically shaped to perfectly match the beam escaping the fiber and to minimize the cell volume. This results in a compact and handy sensor for investigations of biological samples and the monitoring of constituents both in vitro and in vivo. The performance of the fiber-coupled PA sensor is demonstrated by sensing glucose in aqueous solutions. These measurements yield a detection limit of 57 mg/dL (SNR = 1). Furthermore, the fiber-coupled sensor has been applied to record human skin spectra at different body sites to illustrate its flexibility.
Keywords: photoacoustic; quantum cascade laser; spectroscopy; glucose
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MDPI and ACS Style
Kottmann, J.; Grob, U.; Rey, J.M.; Sigrist, M.W. Mid-Infrared Fiber-Coupled Photoacoustic Sensor for Biomedical Applications. Sensors 2013, 13, 535-549.
Kottmann J, Grob U, Rey JM, Sigrist MW. Mid-Infrared Fiber-Coupled Photoacoustic Sensor for Biomedical Applications. Sensors. 2013; 13(1):535-549.
Kottmann, Jonas; Grob, Urs; Rey, Julien M.; Sigrist, Markus W. 2013. "Mid-Infrared Fiber-Coupled Photoacoustic Sensor for Biomedical Applications." Sensors 13, no. 1: 535-549.