Fabrication of UV-curable silicone coating with high transmittance and laser-induced damage threshold for high-power laser system

Third harmonic generating (THG) element is an important component for high-power laser system and its incident side is in need of high transmittance and laser-induced damage threshold (LIDT) at specified wavelengths (1064 nm and 532 nm) to meet the demand of laser-driven inertial confinement fusion. An UV-curable organic–inorganic hybrid silicone coating was fabricated for this THG element and its relevant properties have been investigated. Si–O–Si backbone structure in combination with characteristics from a mixture of tripropyleneglycoldiacrylate (TPGDA) as a reactive diluent and Darocur 1173 (HMPP) as a photoinitiator provided qualified adhesion, hardness, transmittance, and laser damage resistance for the UV-cured coating. Based on this design, THG element with both high transmittance and LIDT at specified wavelengths was successfully achieved after the solidification of coatings by means of UV irradiation, which provides an alternate option to cure coatings upon the temperature-sensitive substrates (like potassium dideuterium phosphate (DKDP), ammonium dihydrogen phosphate (ADP), and so on) without heating, and meanwhile greatly reduces the time consumption of curing process. [Figure not available: see fulltext.]