Highly sensitive refractive index sensor based on TiO2/Ag films coated D-type photonic crystal fibers

• Published in: Optical and quantum electronics Vol. 55; no. 10
• Main Authors: wu, Biao, Chen, Hailiang, Chen, Qiang, Yin, Zhiyong, Wang, Chengjun
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2023; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Computer Communication Networks; Crystal fibers; Electrical Engineering; Film thickness; Finite element method; Hole size; Lasers; Multilayers; Optical Devices; Optics; Organic chemistry; Oxidation; Photonic crystals; Photonics; Physics; Physics and Astronomy; Refractivity; Sensitivity; Silver; Surface plasmon resonance; Titanium dioxide; Photonic crystal fiber; Surface plasmon resonance; Multilayer film
• ISSN: 0306-8919; 1572-817X
• DOI: 10.1007/s11082-023-05149-1

In this paper, we proposed a D-type highly sensitive surface plasmon resonance (SPR)sensor based on multilayer films coated with photonic crystal fiber (PCF). Silver was selected as the plasmon material because its SPR spectrum is sharper than gold. Meanwhile, we used the titania (TiO 2 ) as the second layer film since it could prevent the oxidation of silver and enhance the SPR effect. We simulated the refractive index sensing performances using the finite element method (FEM). This paper optimized the air hole size, polishing depth, silver film thickness, and TiO 2 thickness. The multilayer film structure showed a significant improvement in the wavelength sensitivity of the sensor. The result showed that the maximum sensitivity reached 11,000 nm/RIU, which was increased by 139% compared with a single silver film. The sensor was suitable for accurately detecting the medical treatment and organic chemicals because of its high sensitivity and FOM.