HR laser line mirrors (HR) provide optimized performance at certain wavelength and certain angle of incidence (AOI). Mirror consists of substrate and multilayer coating stacks which help to achieve very high reflectivity at specific laser line wavelength at any designed angle of incidence. Laser line HR coatings are used for external beam manipulation applications where even slight losses may be intolerable. Coatings are provided by electron beam evaporation with/without ion assistance coating technique.
E-beam HR coatings are the most common dielectric coatings in laser optics market as this technology was leading for few decades, and only in recent years this technology started facing competition from other technologies.