The Study Of The Solid Laser Film Damage Threshold Of 1064nm

Optical coatings as an important part of high-energy, high-power laser system are damaged first under laser irradiation, which seriously affect the normal work of the laser system. The research on laser induced damage threshold of optical coatings is of great significance to push laser to high-energy and high-power.Optical coatings has low absorption and scattering loss, high density and good environmental stability prepared by ion beam sputter technology. So, the damage threshold of the optical coatings prepared by ion beam sputtering is studied in this paper.First, the laser induced damage threshold platform was set up, and then measured the different design of antireflection coatings, the high reflection coatings for 45 degree and the coating stacks before and behind the substrate for double-sided coated antireflection coatings. Details are as follows:1.To improve the roundness and intensity distribution of the light spot incident on the optical element which was measured for laser induced damage threshold, we changed the laser-cavity mirror, laser cavity and try to use concave cylindrical lens to shape the light beam. Adding polarization optical element improved the thermally induced depolarization when rotating half-wave plate angle.2.To improve the laser induced damage threshold of dual-wavelength antireflection coatings which were deposited by ion beam sputtered for 1064 nm and 532 nm, a half-wave thickness of the silica layer was deposited near the substrate and the air respectively to investigate the effect of the buffer layer and the protective layer on antireflection coatings for laser induced damage threshold. The experiment results show that a half-wave thickness of buffer layer and protective layer all can improve the antireflection coatings’ damage threshold and finally the laser induced damage threshold of coatings with protective layer and buffer layer increase from 8.14J/cm2 to 17.8621J/cm2 increased by 119% respect to the coatings without buffer layer and protective layer.3.The antireflection coatings were deposited on both sides of the substrate used optimized optical design and were measured the laser induced damage threshold on both sides. The results show that the coatings before the substrate have higher laser induced damage threshold. We analyze the different damage threshold of the coatings before and behind the substrate through the damage morphology.4.Through changing the degree of the half-wave plate in the light path, we measured the laser induced damage threshold of high reflection coatings of 45 degree under S, P polarization incident. The results show that the laser induced damage threshold of 45 degree high reflection coatings under S polarization is higher than P polarization. We use the electric field distribution and the damage morphology to analyze the different laser induced damage threshold under S, P polarization incident.