Abstract

In the past, synchronously pumped OPOs (SPOPOs) have been demonstrated with a variety of nonlinear crystals and pump sources. A non-linear crystal which has attracted strong attention is periodically poled lithium niobate (PPLN). This is due to its large non-linearity, the wide transmission range and the temperature tunability. A disadvantage is certainly the strong pho- torefractivity. To reduce photorefractive damage the crystals have to be heated to temperatures well above 100°C. The threshold for photoreffactive damage can be increased, however, by doping the material with MgO¹ or by using stoichiometric material.²

© 2002 Optical Society of America