High quality factor refractive index sensor based on double-sided all-dielectric two-dimensional grating

This paper presents a symmetric all-dielectric two-dimensional grating with high transmittance and high figure of merit based on cylindrical nanoarrays as a liquid sensing structure with small volume and high sensitivity. The device is optimized using the finite element method to calculate the transmissivity under TE/TM polarization. When the incident angle is 4 degrees, the transmissivity of the grating is nearly 1 with a full width at half maximum of 0.016 nm and a sensitivity of 256.2 nm/RIU. The high figure of merit is 16214.936, and the corresponding quality factor can reach 56572.438. The sensor characteristics of the incident angle on the device are analyzed, and the normalized electric field distribution indicates that the change of the incident angle has a significant modulation ability for the resonance energy distribution. The proposed sensor is independent of polarization state, easy to control and integrate, and has broad application prospects in fields such as liquid solution detection, ocean surveys, and position sensing. Structural parameters can significantly change the full width at half maximum, sensitivity and FOM. Incident angle and transverse longitudinal displacement facilitate dynamic control of sensor performance.Realize the refractive index sensing of different liquid solutions.