Design and Analysis of Ultra-Compact Plasmonic Sensor based on Waveguide-Coupled Structure

摘要

Plasmonic waveguides-based sensors have many advantages in developing the compact on-chip surface plasmon resonance sensing systems. In this paper, a plasmonic refractive index sensor based on two waveguide-coupled cavities structure is proposed and demonstrated. The cavities are symmetrically located on two sides of the waveguide and could act as containers for the material under sensing. The finite difference time domain method is employed to study its sensing characteristics.The simulated results show that the resonant wavelengths of the sensor have a linear relationship with the refractive index of materials under sensing. Based on the relationship, the refractive index of the material can be obtained by detecting the resonant wavelength. Compared with the sensor with a single cavity, the sensor with two cavities has a similar response while has a larger transmission intensity due to the coupling effect between the cavities.