Antireflective laser coating depositing by silicate sol-gel method

Истомина Е.И., Федосеев В.Н., Высоцкая В.В., Жупанов В.Г. Нанесение просветляющего лазерного покрытия силикатным золь-­гель методом // Оптиче­ский журнал. 2023. Т. 90. № 10. С. 108–115. http://doi.org/10.17586/1023­-5086­-2023­-90­-10­-108-115

Istomina E.I., Fedoseev V.N., Vysotskaya V.V., Zhupanov V.G. Antireflective laser coating depositing by silica sol­gel method [In Russian] // Opticheskii Zhurnal. 2023. V. 90. № 10. P. 108–115. http://doi.org/10.17586/1023­-5086-­2023­-90­-10-­108-­115

E. I. Istomina, V. N. Fedoseev, V. V. Vysotskaya, and V. G. Zhupanov, "Deposition of laser antireflection coating by a silicate sol-gel process," Journal of Optical Technology. 90(10), 626-629 (2023). https://doi.org/10.1364/JOT.90.000626

Subject of study. Antireflection SiO₂-coatings on fused silica substrates for high­power pulsed lasers in the near infrared range. Aim of study. Elaboration of technology for depositing antireflection laser coatings on fused silica substrates using the silicate sol­-gel method. Method. The applied sol­-gel method is based on the well­known Stöber-process, which makes it possible to obtain homogeneous spherical silicon dioxide nanoparticles of a controlled size in a colloidal sol solution. The sol was prepared on the basis of tetraethoxysilane, ethyl alcohol, and aqueous solution of ammonia. The coating was applied by immersing the samples and extracting them at a controlled speed. Main results. The main parameters of the sol preparation, the application and heat treatment processes are described. The efficiency of the technology is demonstrated by achievement of high characteristics on the coating samples — the transmission and absorption coefficients, the laser­induced damage threshold obtained by measurements. The coating thickness and refractive index were determined by analyzing the transmission spectra, and the film porosity was calculated using the Lorentz–Lorenz formula. Practical significance. Laser antireflection coatings on fused silica substrates deposited by the silicate sol­-gel method provide higher laser­induced damage threshold and transmission, allow to simplify and cheapen manufacturing equipment, and also they can be applied simultaneously to both surfaces of the optical elements, including non­flat surfaces with a large curvature.