Wideband antireflection coatings by combining interference multilayers with structured top layers.
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.
Schulz
U
U
Fraunhofer Institute of Applied Optics and Precision Engineering, A.-Einstein-Str. 7, 07745 Jena, Germany. ulrike.schulz@iof.fraunhofer.de
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008420:Manufactured Materials; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity