Abstract

Second harmonic generation efficiency can be enhanced by placing the nonlinear crystal in an external cavity that resonates the fundamental, or the second harmonic or both¹. Results of early efforts were disappointing due to poor quality nonlinear materials and multi-mode pump sources. Recently, as a result of advances in both nonlinear crystal growth and diode-pumped solid state laser development, efficient second harmonic generation in an external resonant cavity at power levels of tens of milliwatts has been realized^2,3. As the power level of stable, single frequency lasers continues to increase, there arises the possibility of producing watt-level second harmonic radiation. In this work, we report the generation of 3.5 watts of continuous wave 532 nm radiation by frequency doubling the 8.5 watt output of an injection-locked Nd:YAG laser.

© 1991 Optical Society of America