Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration
Xu Wen-Qi1, Lin Dong-Feng2, Xu Xin2, Ye Jia-Sheng1, †, Wang Xin-Ke1, Feng Sheng-Fei1, Sun Wen-Feng1, Han Peng1, Zhang Yan1, Meng Qing-Bo2, Yang Guo-Zhen2
       

(color online) (a) Boundary profile of the optimized 32-level SSBC DOE. The inset magnifies the local part of the boundary. (b) Output-plane intensity distributions of the optimized 32-level SSBC DOE with the maximum permitted phase of 12π. The grating apex angles are chosen as , , and for incident wavelengths of 0.45, 0.55, and , respectively. The blue, green, and red curves plot the intensity distributions for incident wavelengths of 0.45, 0.55, and , respectively.