Phase-matched frequency doubling in a LiNbO₃-sapphire waveguide

An rf-sputtered thin film of LiNbO3 on a sapphire substrate was used as a waveguide for optical frequency doubling. Employing a Nd laser and a tunable dye laser, whose output was used to pump a stimulated Raman cell, the TMω0→TM2W2 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 10-3. © 1982.