All-Dielectric Metasurface for Highly Tunable, Narrowband Notch Filtering

A novel scheme of an all-dielectric metasurface with double-layer patch array is proposed to achieve the highly tunable, narrowband notch filtering across visible and near-infrared range. The all-dielectric metasurface presents efficient blocking (transmittance 0.01–0.0001) at targeted wavelength and high (>93%) transmission across the visible and near-infrared light range outside the targeted wavelength band. The bandwidth of the notch filter could be greatly compressed with this all-dielectric metasurface, compared with those typical interference notch filters for distinctive wavelengths. The effect of the geometrical parameters on the spectral filtering of this metasurface is studied to provide a distinct relationship to design the desired narrowband notch filter conveniently. And the antireflection effect of the top silicon dioxide layer is verified with similar bandwidth, lower transmission at notch filtering wavelength and higher transmission at other wavelengths. In addition, the optical Fano resonance excited by the all-dielectric metasurface is responsible for the spectral filtering feature including the deep blocking feature at the specific wavelength and high transmission at other wavelengths.