Diode-pumped eye-safe laser source exceeding 1 percent efficiency

An all-solid-state, diode-pumped, eye-safe laser source at 1.61 micron is described, based on an Nd:YAG laser and a noncritically phase-matched KTP optical parametric oscillator. Total energy conversion efficiencies of the 1.064-micron pump to 1.61-micron signal and 3.1-micron idler approach 50 percent, with 35 percent conversion to 1.61 micron alone. This device produces 1.6 mJ at 1.61 micron with a wallplug efficiency of 1.1 percent and is readily scalable to higher energies. Tunability over 1.6 to 1.54 micron is obtained by rotation of the KTP crystal about its z axis, with 1.54-micron output obtained for propagation along the y axis under noncritical phase matching. (Author)