Design of self-coupled plasmonic hyperbolic metamaterials refractive index sensor based on intensity shift

Achieving efficient, accurate, label-free, and real-time biodetection is urgently required; hence, we propose a miniaturized, easily integrated, high-sensitivity plasmonic metamaterial light intensity refractive index sensor. The main structure of the sensor is layered hyperbolic metamaterial grating comprises eight pairs of Au/Al2O3 thin film, and the highly sensitive bulk plasmon polaritons can be effectively excited inside by the self-coupled effect without external prism or nanograting. The periodic fishnet arrays built in the layered HMM structure can not only be used as nanograting to achieve efficient coupling between incident light and layered HMM, but also increase the volume of the sensing, and the measured substance can get full interaction with the enhancement field to obtain high sensitivity. By detecting the change of reflected optical intensity with the ambient refractive index, the sensor exhibits intensity sensitivity of 36 RIU-1 (refractive index unit) and figure of merit of 403; moreover, the full width at half maximum of resonant peak is low at 5 nm. The sensing performances indicate that the sensor we designed has a significant potential to achieve portable, highly sensitive sensing platforms for precise detection.