High-efficiency intracavity frequency doubling of a styryl-9 dye laser with KNbO_3 crystals

Efficient (1.1%) frequency doubling of a low power cw (single frequency) dye laser at 850−870-nm wavelengths in KNbO3 has been demonstrated. The fundamental power on the crystal was enhanced by (i) use of a passive resonator and (ii) by mounting the crystal within the dye laser resonator. The room temperature noncritical phase-matching wavelength for the nonlinear optical coefficient d32 = (20.5 ± 0.3) pm/V has been determined to be λpm = (859.7 ± 0.3) nm for the KNbO3 crystals used in these experiments.