An ultra-narrowband TE-polarization absorber with a dielectric grating and metal substrate

Abstract

We report an ultra-narrowband absorber with a dielectric grating and metal substrate. The simulation results show that we can achieve ultra-narrowband absorption with the absorption bandwidth less than 0.6 nm and the absorption rate more than 0.99 for TE-polarization (electric field is parallel to grating grooves). The simulation results also show the guide-mode resonance in the grating region and low power loss at the absorption peak. In addition, the ultra-narrowband absorption peak can be tuned by shrinking or enlarging the structure parameters. The figure of merit (FOM) is larger than 760 if this absorber is applied as a refractive index sensor.