Improvements in the laser damage behavior of Ta2O5/SiO2 interference coatings by modification of the top layer design

We have investigated the properties and laser damage behavior of Ta2O5/SiO2 quarter wave stacks designed for λ=1 μm operation by substituting the Ta2O5 layer by either Y2O3 or HfO2 and the SiO2 by Al2O3 in the top 3 pairs of the multilayer stack. The high reflectors were deposited by dual ion beam sputtering. Laser damage at 1 μm using 350 ps showed enhanced performance when the Ta2O5/SiO2 stack had HfO2 or Y2O3 in its top few pairs.