Widely tunable nonresonator parametric oscillator generating picosecond light pulses as a result of quasicontinuous pumping

A picosecond parametric oscillator continuously tunable in the range 0.74–1.91μ was constructed from a Ba₂NaNb₅O₁₅ crystal. It was capable of emitting pulses at a repetition frequency up to 4 kHz. The oscillator was pumped by the second harmonic of radiation from a quasi-cw picosecond YAG:Nd³⁺ laser with acoustooptic mode locking and Q switching. A two-pass system in a Ba₂NaNb₅O₁₅ crystal of length 1 cm was employed and the energy conversion efficiency averaged over a train was 0.8%. The spectral width of the radiation was 100 cm^–1 near the degenerate regime and 17 cm^–1 when the detuning was large.