naa a22 4500 510817882 CHVBK 20180411083517.0 cr unu---uuuuu 180411e20130601xx s 000 0 eng 10.1007/s11468-012-9472-z doi (NATIONALLICENCE)springer-10.1007/s11468-012-9472-z Surface Plasmon Resonance Based Fiber Optic Ammonia Sensor Utilizing Bromocresol Purple [Elektronische Daten] [Priya Bhatia, Banshi Gupta] In this paper, a surface plasmon resonance (SPR) based fiber optic ammonia gas sensor has been designed and fabricated using bromocresol purple (BCP) as sensing element. The sensor works under wavelength modulation scheme. The detection of ammonia gas has been carried out at room temperature. Three different kinds of film coating configurations, namely silver + BCP, gold + BCP, and silver + silicon + BCP on the unclad portion of the fiber have been used for studying the role of each layer. Further, to optimize the performance of the sensor, the films of varying thicknesses were coated using thermal evaporation technique. Experiments have been performed for the ammonia concentrations ranging from 0 to 150ppm around the probe. To record the SPR spectrum, light from a polychromatic source is launched in the fiber and the spectrum is recorded at the other end of the fiber. The spectrum has a peak at lower wavelength while a dip at the higher wavelength. The dip corresponds to SPR while the peak appears to be due to fluorescence properties of the dye. It has been observed that as the ammonia gas comes in contact of the BCP layer, it changes the refractive index of the BCP dye which, in turn, changes the resonance wavelength. Further, the change in refractive index increases as the concentration of ammonia gas increases up to certain concentration of ammonia after that it saturates. Silicon layer has been shown as a protection layer for silver and gold from oxidation and acts as a tuner of wavelength. The proposed ammonia sensor has small response as well as recovery time. Springer Science+Business Media New York, 2012 Surface plasmon nationallicence Optical fiber nationallicence Sensor nationallicence Ammonia nationallicence Bromocresol purple nationallicence Bhatia Priya Department of Physics, Indian Institute of Technology Delhi, 110016, New Delhi, India aut Gupta Banshi Department of Physics, Indian Institute of Technology Delhi, 110016, New Delhi, India aut Plasmonics Springer US; http://www.springer-ny.com 8/2(2013-06-01), 779-784 1557-1955 8:2<779 2013 8 11468 https://doi.org/10.1007/s11468-012-9472-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11468-012-9472-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bhatia Priya Department of Physics, Indian Institute of Technology Delhi, 110016, New Delhi, India aut NATIONALLICENCE 700 1- Gupta Banshi Department of Physics, Indian Institute of Technology Delhi, 110016, New Delhi, India aut NATIONALLICENCE 773 0- Plasmonics Springer US; http://www.springer-ny.com 8/2(2013-06-01), 779-784 1557-1955 8:2<779 2013 8 11468 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer