Second-Harmonic Generation Green Laser for Higher-Density Optical Disks

A laser-diode-pumped intracavity frequency-doubled Nd:YAG laser (SHG green laser) is an excellent light source for reading out higher-density optical disks because of its shot-noise-limited output and diffraction-limited beam quality. Scaling of the green laser using a bundle of fibers was successfully demonstrated to obtain more than 1 W of output power. By using the high-power green laser, generation of continuous-wave fourth-harmonic ultra-violet light for future ultrahigh-density optical memory was also demonstrated.