High-efficiency parametric converter based on KTP crystals

A high-efficiency extracavity parametric oscillator based on KTP crystals f or converting radiation of Nd3+ : YAG lasers at 1.064 mu m to radiation at 1.573 mu m is made and its oscillation characteristics are studied. A diffe rential efficiency of 56.5% and a threshold energy density of 0.06 J cm(-2) were obtained. The angular divergence of parametric emission did not excee d four diffraction limits in a wide range of pump energies. The feasibility of stable operation for a more than 30-fold excess of pump energy over the threshold value was obtained.