Disk mastering process with an all-solid-state ultraviolet laser

The mastering process of the optical disk is demonstrated using an all-solid-state ultraviolet laser for the first time. A 355-nm emission is obtained by the nonlinear frequency mixing between 1064nm and 532nm using β-BaB₂O₄ crystal in an external resonator. The laser head is efficient hence it does not require water cooling. A 30% improvement over the argon ion gas lasers is obtained in the track pitch variation with the 0.74μm-pitch-tracks. The absence of the water flow for the cooling is the reason for the improvement. The optics designed at 351 nm turned out to be compatible with the 355-nm laser source.