Sol-Gel preparation of high transmittance of infrared antireflective coating for TeO2 crystals

Abstract

Infrared antireflection (AR) coatings as an important part of infrared components play an important role in the infrared system. Herein, high transmittance of infrared AR coatings were successfully prepared on TeO2 substrate by sol–gel method. Two kinds of sols, including SiO2-TiO2-PVA sol and SiO2-TiO2-PEG600 sol with optimized composition ratio, were designed to prepare AR coatings according to the theory calculation. The microstructures and optical properties were studied by scanning electron microscope and spectrophotometer, respectively. High transmittance of about 99.8% at 1550 nm and 99.6% at 2008 nm, respectively, was achieved in SiO2-TiO2-PVA film coated sample, and the transmittance of about 100% at 2330 nm and 2460 nm, respectively, was achieved in SiO2-TiO2-PEG600 film coated sample. Both AR films have very low roughness, which is conductive to reducing surface scattering. It is found that SiO2-TiO2-PEG600 film shows a more structural stability than SiO2-TiO2-PVA film during annealing. The durability of the films such as adhesion property, water resistance, high and low temperature resistance, and laser tolerance were examined systematically.