Fano resonance sensing based on coupling of a sub-wavelength grating and an all-dielectric multilayer film under angle modulation.

Based on the diffraction effect of the waveguide grating, a hybrid structure of an all-dielectric multilayer film and a sub-wavelength dielectric grating is proposed. The discrete state provided in the sub-wavelength waveguide grating couples with the continuous state provided in the Fabry-Perot cavity (F-P cavity) containing the photonic crystal to form a Fano resonance. The relationship between the structural parameter and the incident angle is analyzed by numerical simulation. The result shows that the figure of merit (FOM) value is 533.2RIU-1. This structure provides an effective theoretical basis for the realization of Fano resonance in the all-dielectric sensing structure.