Refractive index sensor based on double-Fano resonance

Abstract

The invention discloses a refractive index sensor based on double-Fano resonance. The sensor comprises a metal-insulator-metal waveguide; a metal partition in the waveguide takes the waveguide as thecenter, and the two sides of the waveguide are respectively provided with a rectangular cavity A and a rectangular cavity B; the rectangular cavity A is parallel to the waveguide, and the rectangularcavity B is vertical to the waveguide; the width of the metal-insulator-metal waveguide is w; the thickness of the metal partition is dm; the width and height of the rectangular cavity A are respectively L1 and H1; the distance between the rectangular cavity A and the waveguide is G1; the width and height of the rectangular cavity B are respectively L2 and H2; and the distance between the rectangular cavity B and the waveguide is G2. Optical waves can be coupled into the rectangular cavities at the two sides when being transmitted in a waveguide core; when a resonance condition is met, the Fano resonance is formed, and a corresponding resonance peak appears on the transmission spectrum of the Fano resonance. The Fano resonance is a weak coupling effect and is particularly sensitive to changes of structural parameters; the refractive index of filling mediums in the rectangular cavities at the two sides is changed to enable the Fano resonance peak to be deviated, so that the sensing of the refractive index of the medium is realized.

Description

technical field [0001] The invention relates to a refraction index sensor based on double Fano resonance, which can be used in the field of nanometer photonics and the field of integrated optical technology. Background technique [0002] Surface plasmon polaritons (SPPs) are electromagnetic waves formed by the interaction between light waves and free electrons on the metal surface. It is bound on the metal surface, and the energy of the light field is maximum at the interface and rapidly decays to both sides. SPPs can break through the diffraction limit and have a huge local field enhancement effect, which can realize the transmission and processing of nanometer-sized optical information, and provide the possibility for the integration and miniaturization of photonic devices. In addition, its special properties make it have important applications in the fields of micro-nano integrated photonic devices, high-density data storage, super-resolution nanolithography, solar cells,...

AI Technical Summary

Problems solved by technology

Compared with the traditional Lorentzian spectral line, the Fano resonance spectral line is asymmetric and has a very narrow spectral width

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