A novel absorptive thin film for laser welding in optoelectronic device capsulation

A kind of absorptive thin film was designed and used in laser welding of SiO2, Si and LiNbO3. This absorptive thin film of three-layer metal-dielectric-metal structure is designed for further reducing the high reflectance of the Nd:YAG laser beam on the surface of the tin layer that is utilized as solder between the transparent parent materials. The actual absorption of laser energy in experiment exceeds 99%. This combination of absorber and solder transformed the laser energy into heat efficiently and decreased the minimum necessary incident laser power transmitting through the transparent parent materials. As a result, the damage of the parent materials, which is suffered from laser transmission, was avoided; On the other hand, mechanical stability of the welded materials had been improved. Experiment had been made to show the difference between welding with and without the absorptive thin film.