Visible picosecond pulse generation in a frequency doubled optical parametric oscillator based on LiB3O5

We report the attainment of transform-limited pulses across the entire tuning range of a high-repetition-rate, synchronously-pumped picosecond optical parametric oscillator (SPOPO) based on LiB3O5, by the inclusion of dispersion compensation in the positive dispersive regime of the crystal. This system which is synchronously pumped by 1.1 ps pump pulses from a self-mode-locked Ti:sapphire laser at 81 MHz, generated transform-limited signal pulses with durations of 1-1.2 ps and idler pulses with durations of 2-2.2 ps over the continuous wavelength range of 1.16-2.26 mu m at average powers of 580 mW, By external frequency doubling output signal pulses from the SPOPO in noncritically phase-matched, temperature-tuned LiB3O5, We have produced transform-limited picosecond pulses in the visible range from 584 to 771 nm at average powers of up to 68 mW, Second harmonic pulses with durations between 840 and 880 fs have been obtained for signal durations of 1-1.2 ps.