Scribing and cutting of sapphire wafer with Q-switched Nd:YAG laser

Transparent and hard materials such as sapphire are used for many industrial applications such as optical windows, hard materials on mechanical contact against abrasion, and buffer materials for semiconductor emitting device etc. Even the harder materials such as diamond are usually used to scribe and cut the materials to be used for various applications, while it has a problem of abrasion of the harder material itself and a problem of limit in shape of cut. The material is also known to be cut by the laser with very high peak power or with a wavelength possible to be easily absorbed in the material. But the lasers are usually accompanied with an economical problem of their high cost. We demonstrated, for the first time in my knowledge, that transparent materials can be scribed and cut freely by sparks induced by a Q-switched Nd:YAG laser beam focused on the metal surface.