Development of Materials Integration for Laser Gain Media: Single Crystals and Ceramic (Polycrystalline) Materials and Applications

Processes for chemical mechanical polishing of yttrium aluminum garnet (YAG) and yttria (Y 2 O 3 ) using commercial slurries have been developed for subsequent bonding applications. Single crystal and polycrystalline surfaces are polished to below 0.5 nm RMS surface roughness, with a controllable polishing rate of 0.3 nm / min. In addition, high resolution x-ray diffraction measurements show a reduction of subsurface damage after polishing these commercially available substrates. Surfaces are generated with < 0.5 nm RMS surface roughness are suitable for wafer bonding, and are treated with various surface preparation steps prior to bonding. Once bonded at room temperature, samples are heated at 1425° C for 72 hours to further strengthen the bond.