Broadband HR coatings are also all dielectric multilayer stacks, like single or multiwavelength HR coatings. However, different thicknesses of the layer pairs ensure much wider high reflection region, like 400-700 nm, 500-700 nm, 600-850 nm, 700-1100 nm, etc.

 

Broadband HR coatings are also sensitive to considerable changes (>10 deg) in incident angle. Coatings, designed for normal incidence usually have R>99%, while coatings designed for non-normal incident angle exibit R>97-98%. However, actual values could be better or worse, depending on width of high reflection range.

 

Broadband HR coatings are all dielectric and therefore superior to metallic coatings for reflectivity, durability, and laser damage resistance.