A High-Sensitivity Refractive-Index Sensor Based on Plasmonic Waveguides Asymmetrically Coupled with a Nanodisk Resonator

• Published in: Chinese physics letters Vol. 32; no. 7; pp. 13 - 16
• Main Author: 肖丽萍 王发强 梁瑞生 邹世伟 胡淼
• Format: Journal Article
• Language: English
• Published: 01.07.2015
• Subjects: Asymmetry; Detection; Mathematical analysis; Nanostructure; Resonators; Sensors; Waveguides; Wavelengths; 传感器; 圆盘形; 折射率; 等离子体波导; 耦合; 谐振器; 非对称; 高灵敏度
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/32/7/070701

A high-sensitivity plasmonic refractive-index sensor based on the asymmetrical coupling of two metal-insulator- metal waveguides with a nanodisk resonator is proposed and simulated in the finite-difference time domain. Both analytic and simulated results show that the resonance wavelengths of the sensor have an approximate linear relationship with the refractive index of the materials which are filled into the slit waveguides and the disk- shaped resonator. The working mechanism of this sensor is exactly due to the linear relationship, based on which tile refractive index of the materials unknown can be obtained from the detection of the resonance wavelength. The measurement sensitivity can reach as high as 6.45 × 10-7, which is nearly five times higher than the results reported in the recent literature [Opt. Commun. 300 （2013） 265]. With an optimum design, the sensing value can be further improved, and it can be widely applied into the biological sensing. Tile sensor working for temperature sensing is also analyzed.