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Proceedings Paper

Comparison of sensitivity between in-situ and ex-situ detections with nanoporous TiO2 film based plasmon waveguide resonance sensor
Author(s): Xiumei Wan; Dan-feng Lu; Zhi-mei Qi
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Paper Abstract

Plasmon waveguides were fabricated by coating sol-gel copolymer templated nanoporous TiO2 films on gold layers sputtered on glass substrates, and they were used to construct wavelength-interrogated plasmon waveguide resonance (PWR) sensors with Kretschmann configuration. The cross-sectional image of the plasmon waveguide obtained with scanning electron microscope indicates that the gold and nanoporous TiO2 films are about 40 nm and 290 nm thick. The resonance wavelength (λR) of the PWR sensor at a given incident angle is determined from either the reflected light intensity spectrum or the absorption spectrum. The porosity of TiO2 film was determined to be ca. 0.42 by a comparison between simulation and experimental results. The PWR sensor operates with transverse electric mode. The in-situ and ex-situ responses of the PWR sensor to glutathione (GSH) adsorption were investigated theoretically and experimentally. The simulation results show that with either in-situ or ex-situ measurement the resonance wavelength linearly increases with increasing GSH concentration and the slope with ex-situ method is 6 times larger than that with in-situ method. The PWR sensor’s response to GSH adsorption from the 100 μmol/L solution was measured to be ΔλR = 31 nm with ex-situ detection and ΔλR = 6.1 nm with in-situ detection. Both the experimental and simulation investigations reveal that the ex-situ detection sensitivity is much higher than the in-situ one for the PWR sensor. The work suggests that the ex-situ detection method can offer the PWR sensor a lower detection limit in contrast with the in-situ method.

Paper Details

Date Published: 10 February 2017
PDF: 8 pages
Proc. SPIE 10250, International Conference on Optical and Photonics Engineering (icOPEN 2016), 1025027 (10 February 2017); doi: 10.1117/12.2267048
Show Author Affiliations
Xiumei Wan, Institute of Electronics (China)
Dan-feng Lu, Institute of Electronics (China)
Zhi-mei Qi, Institute of Electronics (China)

Published in SPIE Proceedings Vol. 10250:
International Conference on Optical and Photonics Engineering (icOPEN 2016)
Anand Krishna Asundi; Xiyan Huang; Yi Xie, Editor(s)

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