Open AccessWideband antireflection coatings by combining interference multilayers with structured top layers
Author(s) -
Ulrike Schulz
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.008704
Subject(s) - refractive index , materials science , optics , interference (communication) , stack (abstract data type) , wideband , layer (electronics) , reflection (computer programming) , wavelength , residual , optoelectronics , composite material , channel (broadcasting) , telecommunications , physics , algorithm , computer science , programming language
The residual reflectance obtained for a broad wavelength range depends mainly on the refractive index of the last layer. Using interference layer stacks composed of naturally available low- and high-index materials, the residual reflection for a broad range cannot be adjusted below a certain limit. However, nanostructured (gradient) and porous layers are effective media with a refractive index lower than that of natural materials. Results demonstrate that an interference layer stack combined with a structured layer as the last layer yields better antireflection properties owing to the low effective index of the structure.