Graded index broadband antireflection coating prepared by glancing angle deposition for a high-power laser system

This paper reports that SiO₂ is selected to fabricate broadband antireflection (AR) coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of the graded index of the SiO₂ layer, transmittance of the graded broadband AR coating can achieve an average value of 98% across a spectral range of 300--1850 nm. Moreover, a laser-induced damage threshold measurement of the fabricated AR coating is performed by using a one-on-one protocol according to ISO11254-1, resulting in an average damage threshold of 17.2 J/cm^2.