Five-layer quarter-wave antireflective coatings for the IR region

This paper discusses the conditions for obtaining the structure of a five-layer antireflection interference coating that contains layers of different thicknesses. Regions of allowable values are given for the refractive index of the layers that form this coating and make it possible to obtain three or five zero values of the reflectance. The resulting structures of five-layer coatings create the possibility of reducing the reflectance of optical materials with either high or low refractive indices. The given coatings are capable of reducing the reflectance in several spectral regions simultaneously. (C) 2014 Optical Society of America.