Ultra-narrowband mid-infrared absorber based on Mie resonance in dielectric metamaterials

Ultra-narrowband absorbers can be applied in many applications. We propose a mid-infrared ultra-narrowband absorber with TM polarization (magnetic field is parallel to grating grooves) based on dielectric metamaterials in this paper. The simulation results show that the absorption rate larger than 0.99 can be achieved at the resonance wavelength, and the absorption bandwidth is less than 10 nm. The simulated field distribution shows that the ultra-narrowband absorption in this absorber originates from Mie resonance. In addition, the absorber preserves high absorption rates up to 4 degrees which means that our absorber has high directivity. Our results show that the ultra-narrowband absorbers can be applied as a thermal emitter.