We report frequency doubling of a low-power cw diode laser at 1064 nm in an external ring cavity by use of an angle-tuned KTP type II crystal. We demonstrate a new setup that requires no temperature stabilization of the crystal. An intracavity λ/2 plate rotates the polarization of the fundamental after each cavity round trip by 90°; this provides the two eigenpolarizations of the crystal required for a type II nonlinear process. As a result, it is possible to maintain the resonance condition by use of a standard locking circuit.
© 1999 Optical Society of America
Yves Emery, Anett Fleischhauer, Thomas Walther, and Edward S. Fry, "Angle-Tuned Type II External-Cavity Frequency Doubling Without Temperature Stabilization," Appl. Opt. 38, 972-975 (1999)