Abstract

Efficient, diode-laser-based sources of blue radiation are useful for applications such as optical storage and laser printing. Blue light can be generated by nonlinear upconversion processes such as Second Harmonic Generation. (SHG) and Sum Frequency Mixing (SFM) to convert the output of reliable, high- power infrared diode lasers to shorter wavelengths. The conversion efficiency can be increased substantially by placing the nonlinear crystal inside of a resonator in order to increase the infrared intensity in the crystal. The buildup of a high infrared intensity and efficient generation of blue output requires precise frequency matching of the diode laser and the resonator. We describe various frequency-locking techniques and their application to resonator-enhanced SHG and SFM of diode lasers for producing blue output powers up to several tens of milliwatts.

© 1993 Optical Society of America