We generated diffraction-limited laser radiation that is continuously
tunable from 3.1 to 4.4 mu m by mixing the output from a Ti:sapphire l
aser with the intracavity field of a single-frequency, 1.064-mu m Nd:Y
AG ring laser. A peak output power of 300 mu W was observed near 3.2 m
u m at a Ti:sapphire input power of 300 mW.