Al2O3/SiO2 and HfO2/SiO2 dichroic mirrors for UV solid-state lasers

HfO2/SiO2 and Al2O3/SiO2 multilayers to be employed as high reflectance end mirrors in Cerium-doped fluoride solid-state lasers were produced by radio frequency sputtering. The components were designed to have high transmittance at the pumping wavelength and high reflectance in a wavelength band corresponding to the active medium emission. A photoacoustic beam deflection technique and inspection of the irradiated area under a microscope were used to measure the laser induced damage threshold of the mirrors at the pumping wavelength. These coatings were tested in a laser cavity.