本文提出并利用时域有限差分(FDTD)模拟了一种新型的金属–介质–金属(MIM)波导结构的表面等离子体传感器,该传感器由一个直主波导和一个共振腔构成。理论分析和模拟结果都证明了传感器的共振波长与待测物质折射率有线性关系。基于这个线性关系,待测物质的折射率可以通过探测共振波长而获得。传感器介质折射率的灵敏度能达到10?6,有望能应用于高分辨率的生物传感。A high-resolution plasmonic refractive-index sensor based on a metal-insulator-metal structure consisting of a straight bus waveguide and a resonator waveguide is proposed and numerically simulated by using the finite differ- ence time domain method under a perfectly matched layer absorbing boundary condition. Both analytic and simulated results show that the resonant wavelengths of the sensor have a linear relationship with the refractive index of material under sensing. Based on the relationship, the refractive index of the material can be obtained from the detection of one of the resonant wavelengths. The resolution of refractive index of the nanometeric plasmonic sensor can reach as high as 10?6, giving the wavelength resolution of 0.01 nm. It could be applied to highly-resolution biological sensing.
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