Study on transmission spectrum and electric field distribution of graded-index anti-reflection coatings

Optical anti-reflection coating is one of the important components of high-energy, high-power laser systems. Under laser irradiation, it is most likely to be destroyed. In this paper,three different inhomogeneous coatings were designed without changing the target transmittance, they were differently graded. In order to further analyze the relationship between different graded-index anti-reflection coatings and laser-induced damage threshold, the transmission spectrum and electric field distribution of graded-index anti-reflection coatings are studied. First of all, the average transmittance of the coatings in the visible region are not less than 99% , then three different inhomogeneous coatings are graded into different layers . When the number of gradient layers increases, the results show that the transmittance and the electric field intensity of substrate and coating interface layer does not change much, the electric field intensity at the interface between the air and coating first increases and then decreases, the sum of interfaces electric field intensity increases continuously.