Subwavelength structured surfaces with a broadband antireflection function are analyzed by using a finite difference time domain method. The 2D periodic pure conical and pyramidal structures and several composite structured surfaces composing of conical and pyramidal structures are presented and discussed. It is found that the antireflection function will decrease for the same size of structures when the structure arrangement is discontinuous and the results of the structures with an aspect ratio of 2.0 are obviously better than the 1.0. It is also found that some composite structured surfaces have powerful antireflection function in the spectral ranges of 400-1400 nm within the 800-1200 nm spectral ranges. (C) 2009 Elsevier GmbH. All rights reserved.
