s Design of One-dimensional Nickel Grating Based Broadband Absorber

Background: Electromagnetic wave absorbers that has near perfect performance have been studied since 2008, various one dimensional and two dimensional structures have been optimized. High absorption at certain frequency can be easily realized. However, high absorption that covers broad band is relatively hard to realized. Method: In this paper, a nickel nanograting is designed by using rigorous coupled wave analysis theory. The effect of grating height and grating width on absorption performance is analyzed physically by using equivalent medium theory and Fabry-Pérot resonate theory. Results: Because of the intrinsic absorption character and the influence of F-P resonance, TM absorption shows periodically increase with the increasing of metal thickness. Absorption of the TE polarization slightly increases with the increasing of grating height. Peak absorption of TM polarization light can be gotten when DC of 0.52 is chosen, however, absorption performance of TE polarization light degrades seriously. In this paper, DC of 0.19 is chosen. Conclusion: A one dimensional nickel grating based broadband absorber is analyzed in this paper. The proposed absorber has good absorption performance over the visible band, and shows no clear degradation over a wide incident angle (-40° to 40°).