Highly efficient high-repetition-rate tunable all-solid-state optical parametric oscillator

A compact highly efficient intracavity optical parametric oscillator (OPO) is demonstrated by placing an OPO cavity in a diode-pumped Q-switched Nd:YLF laser. By taking into account the thermal and energy upconversion transfer effects of Nd:YLF, a power scaling model is set up to optimize and design a fundamental mode diode-pumped Nd:YLF laser. The linearly polarized Nd:YLF laser in the 1053-nm line generates 6.5, 9.2, and 11.9 W average power in TEM/sub 00/ mode at the repetition rates of 1, 2, and 4.5 kHz, respectively. A highly efficient OPO signal output is realized by using an optimized cavity design. We obtain OPO average signal powers of more than 1 W over a broadband continuous tuning range from 1650 to 2100 nm at the repetition rate of 1 kHz. The OPO signal pulsewidth is 10 ns at 1 kHz. Signal energies of 2.5, 1.55, and 0.67 mJ per pulse are produced at the repetition rates of 1, 2, and 4.5 kHz, respectively. The maximum OPO signal energy of 2.5 mJ per pulse is obtained at 1900 nm, where the pump energy is 6 mJ per pulse and the pump-to-signal efficiency is 42%. A maximum average signal power of 4.1 W is generated at 3.5 kHz.