Comparative research on characteristics of light absorbers of metal-dielectric and metal photonic crystal transmission grating

Using nanofabricated Si3N4 nanohole array photonic crystal grating, an Au metal-dielectric resonance grating by spin-coating Au on the Si3N4 nanohole array photonic crystal grating is investigated. Optical properties and related characteristics of metal-dielectric grating light absorber and meal grating light absorber are compared and analyzed. We simulate transmittances corresponding to different grating periods of the metal-dielectric photonic crystal transmission grating in visible-infrared light region and display electric field distributions in the vicinity of nanoholes at different incident wavelengths by using finite-difference time-domain (FDTD) software with broadband light source 400 nm-1100 nm.The mechanism of absorption generation in the metal-dielectric and metal transmission grating is analyzed and discussed in this paper. The Au structure of metal photonic crystal transmission grating is also investigated for light absorber. The metal-dielectric photonic crystal transmission grating structure absorbs more than 90% of the incident light at absorption point wavelength.