Blue laser devices for optical data storage (Invited Paper)

A number of different techniques have been used for nonlinear frequency upconversion of near-infrared semiconductor diode lasers to blue wavelengths. Intracavity frequency doubling of a diode-laser-pumped 946-nm Nd laser resulted in generation of 9.5 mW of blue 473- nm power. A special electronic servo technique was devised to lock the output frequency of a single-mode GaAlAs diode laser to a monolithic KNbO3 resonator. Using this approach, 54 mW of 428-nm output were obtained with an electrical-to-optical conversion efficiency of approximately 12%. The use of nonlinear waveguide devices for frequency doubling of near- infrared diode lasers is promising for the development of miniaturized, low-cost blue laser sources.