Surface plasmon polariton assisted near perfect light absorption from corrugated metal–insulator–metal structure exploiting lossy metal films

We propose and demonstrate a lithography-free self-assembled corrugated Cr/TiO2/Cr metal-insulator-metal (Cr-cMIM) structure on silica opal substrates for broadband near perfect light absorption applications. Our optimal Cr-cMIM structure have reached a spectral average absorption rate above 98% over the visible wavelength range. We carried out numerical calculations to simulate the interaction between the incident light and the Cr-cMIM structure. The simulated absorption spectra qualitatively reproduced the experimental results. Detailed analysis of the simulation results indicates that the corrugation of the Cr layers successfully couples the incident light with the localized surface plasmon polariton. The incorporation of the surface plasmonic excitation and the intrinsic ohmic dissipation of the Cr layers results in the broadband near perfect light absorption over the visible wavelength range.