Comparison of sensitivity between in-situ and ex-situ detections with nanoporous TiO2 film based plasmon waveguide resonance sensor

Xiumei Wan; Dan-feng Lu; Zhi-mei Qi

doi:10.1117/12.2267048

10 February 2017 Comparison of sensitivity between in-situ and ex-situ detections with nanoporous TiO₂ film based plasmon waveguide resonance sensor

Xiumei Wan, Dan-feng Lu, Zhi-mei Qi

Author Affiliations +

Proceedings Volume 10250, International Conference on Optical and Photonics Engineering (icOPEN 2016); 1025027 (2017) https://doi.org/10.1117/12.2267048
Event: Fourth International Conference on Optical and Photonics Engineering, 2016, Chengdu, China

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 (λ_R) 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 Δλ_R = 31 nm with ex-situ detection and Δλ_R = 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.

Citation Download Citation

Xiumei Wan, Dan-feng Lu, and Zhi-mei Qi "Comparison of sensitivity between in-situ and ex-situ detections with nanoporous TiO₂ film based plasmon waveguide resonance sensor", Proc. SPIE 10250, International Conference on Optical and Photonics Engineering (icOPEN 2016), 1025027 (10 February 2017); https://doi.org/10.1117/12.2267048

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