Efficient optical parametric oscillator at 1.6 microm

We extend the operating regime of diode-pumped Nd:YAG lasers into the eye-safe region at 1.61 microm by using an efficient optical parametric oscillator in KTP. Total energy conversion efficiencies of the 1.06-microm pump to 1.61-microm signal and 3.1-microm idler approach 40%, with 25% converson to 1.61microm alone. This device has a wallplug efficiency of 0.8%, producing 2.5-mJ output energies at an eye-safe wavelength, and is readily scalable to higher energies.