Fano resonance characteristics of a silicon notched disk metasurface-waveguide system under different polarization conditions

Abstract

Abstract In this paper, we design and theoretically investigate a silicon notched disk metasurface-waveguide (NDMW) system, realizing a new approach to excite Fano resonance by introducing a waveguide layer to generate quasi-guided mode (QGMs) resonances. By comparing the transmission characteristics of the silicon complete disk metasurface (CDM), the silicon complete disk metasurface-waveguide (CDMW) system, and the NDMW system, the formation mechanism of Fano resonances in multiple different excitation modes is analyzed. Furthermore, the Fano resonance characteristics of the NDMW system for different polarization conditions are studied. It can be found that different polarization states can excite different multiple Fano resonances in the NDMW system. Finally, the effects of various structural parameters on the multiple Fano resonances characteristics are investigated. Utilizing the narrow linewidth and significant near-field confinement of the Fano resonances, an optical refractive index sensor can be obtained with the sensitivity of 113 nm RIU−1 and the maximum quality (Q) factor of 2 × 10 5 . The proposed system opens up an avenue to develop high-performance biological sensors.