Angle-tuned type II external-cavity frequency doubling without temperature stabilization.
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 lambda/2 plate rotates the polarization of the fundamental after each cavity round trip by 90 degrees; 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.
Emery
Y
Y
Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA.
Fleischhauer
A
A
Walther
T
T
Fry
E S
ES