High-power narrow-band pulses with wavelengths tunable about 1.053 μm from a synchronously pumped optical parametric oscillator

We have constructed an optical parametric oscillator to generate 75-ps near-transform-limited pulses with wavelengths tunable about 1.053 μm for use in pump–probe studies of self-focusing. The singly resonant oscillator uses a Brewster-cut LiB_3O_5 crystal that is oriented for type-II phase matching and synchronously pumped by the amplified and frequency-tripled pulse trains from a mode-locked and Q-switched Nd:YLF laser. An intracavity Pockels cell is used to switch out single 0.5–MW pulses at rates of 1 to 10 Hz. The design, construction, and performance of the oscillator are discussed. Measured performance is compared with design predictions and with detailed numerical simulations.