title: A hydrogen curing effect on surface plasmon resonance fiber optic hydrogen sensors using an annealed Au/Ta₂O₅/Pd multi-layers film.
abstract: In this paper, a response time of the surface plasmon resonance fiber optic hydrogen sensor has successfully improved with keeping sensor sensitivity high by means of hydrogen curing (immersing) process of annealed Au/Ta2O5/ Pd multi-layers film. The hydrogen curing effect on the response time and sensitivity has been experimentally revealed by changing the annealing temperatures of 400, 600, 800°C and through observing the optical loss change in the H2 curing process. When the 25-nm Au/60-nm Ta2O5/10-nm Pd multi-layers film annealed at 600°C is cured with 4% H2/N2 mixture, it is found that a lot of nano-sized cracks were produced on the Pd surface. After H2 curing process, the response time is improved to be 8 s, which is two times faster than previous reported one in the case of the 25-nm Au/60-nm Ta2O5/3-nm Pd multi-layers film with keeping the sensor sensitivity of 0.27 dB for 4% hydrogen adding. Discussions most likely responsible for this effect are given by introducing the α-β transition Pd structure in the H2 curing process.
authors.forename: Ai
authors.initials: A
authors.lastname: Hosoki
authors.forename: Michiko
authors.initials: M
authors.lastname: Nishiyama
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Igawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Watanabe