Direct Bonding of Ti:sapphire laser Crystals.

Direct bonding without the use of adhesive materials was demonstrated on a titanium-doped sapphire laser crystal with a bonding surface dimension of 12 mm x 6 mm(2). The bonding surfaces were treated with chemical processes to clean up and to create a hydrophilic (-OH) thin layer for hydrogen bonding. Two different processes of heat treatment performed in succession transformed the hydrogen bonding into direct bonding. The performance of the bonded crystal was tested by laser oscillation with the second harmonics of a Q-switched Nd:YAG laser at a 20-Hz repetition rate. In comparison with a normal laser crystal, there were no differences in output power or spatial profile in an input pumping condition of 30 mJ.