Abstract
An rf‐sputtered thin film of LiNbO3 on a sapphire substrate was used as a waveguide for optical frequency doubling. Employing a Nd:YAG laser and a tunable dye laser, whose output was used to pump a stimulated Raman cell, the TMω0 → TM2 up‐conversion process was investigated in detail, and the phase‐matched nature of this process was demonstrated. The conversion efficiency was estimated to be about 103.