Abstract

Nonlinear frequency conversion of laser diodes and diode-pumped solid-state lasers provides potential sources of coherent laser radiation in the blue spectral region. Two efficient methods based on nonlinear frequency conversion are the direct doubling of laser diodes and intracavity doubling of the 946nm transition of Nd:YAG. Both of these methods however, require the use of Potassium Niobate. Although this crystal has a relatively large nonlinear coefficient, it is difficult to polish and depoles into multiple ferroelectric domains under slight stress or excessive temperature cycling. Reorientation of the domains lowers the effective crystal nonlinearity and produces domain walls which appear as 'cracks' within the bulk medium. These properties may well limit the application of KNbO₃ in commercial devices.

© 1992 Optical Society of America