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
Original Manuscript: July 27, 1998
Revised Manuscript: October 12, 1998
Published: February 20, 1999
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)