Sensitivity Enhanced Refractive Index Fiber Sensor Based on Long-Range Surface Plasmon Resonance in SiO2-Au-TiO2 Heterostructure

Bu, Wenyi1; Wu, Zhifang1; Shum, Perry Ping2; Shao, Xuguang3; Pu, Jixiong1

2021-09-01

10.3390/photonics8090379

PHOTONICS   影响因子和分区

2304-6732

Long-range surface plasmon resonance (LRSPR), generated from a coupled plasmon polariton in a thin metal slab sandwiched by two dielectrics, has attracted more and more attention due to its merits, such as longer propagation and deeper penetration than conventional single-interface surface plasmon resonance. Many useful applications related to light-medium interaction have been demonstrated based on the LRSPR effect, especially in the sensing area. Here, we propose and demonstrate an LRSPR-based refractive index sensor by using a SiO2-Au-TiO2 heterostructure, in which a D-shaped honeycomb-microstructure optical fiber (MOF) is designed as the silica substrate and then deposited with a gold film and thin-layer titanium dioxide (TiO2). By using the full-vector finite-element method (FEM), this heterostructure is numerically investigated and demonstrated to excite LRSPR without a buffer layer, which is usually necessary in previous LRSPR devices. Through comprehensive discussion about the influence of structural parameters on the resonant wavelength, the excitation of the LRSPR in the proposed heterostructure is revealed to be highly related to the effective refractive index of MOF's fundamental core mode, which is mainly determined by the MOF's pitch, the thicknesses of the silica web and the planar-layer silica. Moreover, the thin-layer TiO2 plays an important role in significantly enhancing the resonance and the sensitivity to analyte's refractive index as well, when it is coated on the top of the Au film rather than between the metal and waveguide. Finally, the proposed LRSPR sensor based on SiO2-Au-TiO2 heterostructure shows an ultra-high wavelength sensitivity of 20,100 nm/RIU and the corresponding minimum resolution is as low as 4.98 x 10(-7) RIU. Thus, the proposed LRSPR device offers considerable potential for sensing applications in biomedical and biochemical areas.

SiO2-Au-TiO2 heterostructure long-range surface plasmon resonance microstructured optical fiber fiber sensor

SCI

英语

其他

National Natural Science Foundation of China[11774102] ; Scientific Research Funds and Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University["ZQN-YX504","17BS412"]

Optics

Optics

WOS:000701109900001

MDPI

Web of Science

1.Huaqiao Univ, Coll Informat Sci & Engn, Fujian Key Lab Light Propagat & Transformat, Xiamen 361021, Peoples R China
2.Southern Univ Sci & Technol, Dept Elect & Elect Engn, Shenzhen 518055, Peoples R China
3.Nanyang Technol Univ, Sch Elect & Elect Engn, 50 Nanyang Ave, Singapore 639798, Singapore

Bu, Wenyi,Wu, Zhifang,Shum, Perry Ping,et al. Sensitivity Enhanced Refractive Index Fiber Sensor Based on Long-Range Surface Plasmon Resonance in SiO2-Au-TiO2 Heterostructure[J]. PHOTONICS,2021,8(9).

Bu, Wenyi,Wu, Zhifang,Shum, Perry Ping,Shao, Xuguang,&Pu, Jixiong.(2021).Sensitivity Enhanced Refractive Index Fiber Sensor Based on Long-Range Surface Plasmon Resonance in SiO2-Au-TiO2 Heterostructure.PHOTONICS,8(9).

Bu, Wenyi,et al."Sensitivity Enhanced Refractive Index Fiber Sensor Based on Long-Range Surface Plasmon Resonance in SiO2-Au-TiO2 Heterostructure".PHOTONICS 8.9(2021).