P1OS.11 - Study on Absorption of VOCs into PDMS Film using Heterodyne Interferometry for Application of VOCs Sensing.
- Event
- 17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
Vienna, Austria - Chapter
- P-1 - Optical Sensors
- Author(s)
- D. Newport, S. Khan - 1Department of Mechanical Aeronautical & Biomedical Engineering, Bernal Institute, University of Limerick, Limerick (Ireland), S. Le Calvé - University of Strasbourg, Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES), Group of Atmospheric Physical Chemistry, Strasbourg (France)
- Pages
- 637 - 638
- DOI
- 10.5162/IMCS2018/P1OS.11
- ISBN
- 978-3-9816876-9-9
- Price
- free
Abstract
A heterodyne interferometer using a Mach-Zehnder optical configuration is designed for detection of airborne VOCs. The design is based on film-mediated sensing technique in which the response of intermediate sensing film is monitored using interferometry. PDMS is used as a sensing film, which changes its volume and refractive index when absorbed VOCs molecules. Thin film of PDMS acts as a phase object and any variation in its state causes a proportional phase shifts in the transmitted light beam. The Mach-Zehnder interferometer is integrated with a microscope and acoustic-optic modulators. The information of the absorbed gas concentration into the film are encoded in the fringe patterns and are extracted by a temporal phase extraction heterodyne method. The film is exposed to different concentrations of air-borne toluene and its response is measured using interferometry.