We review the physical properties, linear and nonlinear optical characteristics, and phase-matching configurations of BiB3O6 (BIBO), the first low-symmetry (monoclinic) inorganic nonlinear crystal that has found broad applications for frequency conversion of laser sources from the UV, across the visible, to the near-IR based on three-wave interactions. We describe in detail the most relevant optical properties that make this material an attractive candidate for nonlinear frequency conversion of laser light in general, and ultrafast femtosecond laser sources in particular. With special focus on ultrafast frequency conversion, characteristics such as group-velocity mismatch and spectral acceptance, parametric gain bandwidth, group-velocity dispersion, as well as angular acceptance and spatial walk-off are evaluated and optimum configurations for the attainment of maximum conversion efficiency, minimum pulse duration, and highest spatial beam quality are identified and compared with the most widely established alternative borate crystal, β-BaB2O4. Experimental results are presented on both parametric up-and down-conversion of femtosecond pulses, from the high-energy, low-repetition-rate (1 kHz) to the low-energy, high-repetitionrate (56-76 MHz) regime, demonstrating the unique versatility of BIBO for efficient frequency conversion of femtosecond pulses with broad tunability from 250 nm in the UV, throughout the visible, up to ∼ 3000 nm in the IR.Photograph of a femtosecond synchronously pumped optical parametric oscillator (SPOPO) based on BiB3O6 emitting in the yellow region of the spectrum. Pumped near 400 nm in the blue by the second harmonic of a Kerr-lens mode-locked Ti:sapphire laser, the SPOPO can generate femtosecond pulses across the full visible range of 480-710 nm, from the blue-green, through to yellow, orange and red.

We report a high-power picosecond optical parametric oscillator (OPO) synchronously pumped by a Yb fiber laser at 1.064 μm, providing 11.7 W of total average power in the near to mid-IR at 73% extraction efficiency. The OPO, based on a 50 mm MgO:PPLN crystal, is pumped by 20.8 ps pulses at 81.1 MHz and can simultaneously deliver 7.1 W of signal at 1.56 μm and 4.6 W of idler at 3.33 μm for 16 W of pump power. The oscillator has a threshold of 740 mW, with maximum signal power of 7.4 W at 1.47 μm and idler power of 4.9 W at 3.08 μm at slope efficiencies of 51% and 31%, respectively. Wavelength coverage across 1.43-1.63 μm (signal) and 4.16-3.06 μm (idler) is obtained, with a total power of ~11 W and an extraction efficiency of ~68%, with pump depletion of ~78% maintained over most of the tuning range. The signal and idler output have a single-mode spatial profile and a peak-to-peak power stability of ±1.8% and ±2.9% over 1 h at the highest power, respectively. A signal pulse duration of 17.3 ps with a clean single-peak spectrum results in a time-bandwidth product of ~1.72, more than four times below the input pump pulses.

We demonstrate the generation of femtosecond pulses in a synchronously pumped optical parametric oscillator (SPOPO) at the harmonics of pump repetition rate using a SPOPO cavity longer than the fundamental synchronous length. The SPOPO is based on a 1 mm crystal of periodically poled LiNbO(3) and pumped by a Kerr-lens mode-locked Ti:sapphire laser at 76 MHz. By increasing the SPOPO synchronous cavity length we have generated output signal pulses at successive harmonics of the pump repetition rate up to the 13th harmonic at 988 MHz, where average signal powers of 30 mW are still available for 1.45 W of pump power. The generated signal pulses at 988 MHz are near transform limited with average durations of 227 fs and a time-bandwidth product of 0.41 for 185 fs input pump pulses.

We report efficient generation of tunable femtosecond pulses in the red by internal frequency doubling of an optical parametric oscillator (OPO) based on periodically poled LiNbO3 (PPLN). The OPO, based on a 1-mm-thick PPLN crystal, is synchronously pumped by a femtosecond Ti:sapphire laser at 810 nm, providing signal pulses across 1.33-1.57 microm at a 76 MHz repetition rate. Using a 1-mm-thick crystal of BiB3O6 (BIBO) internal to the OPO cavity, we achieve frequency doubling of signal pulses across 665-785 nm with up to 260 mW of average power for 1.51 W of pump. The high nonlinear gain and phase-matching acceptance in PPLN and BIBO permit convenient tuning across the full range by simple detuning of OPO cavity delay. Intracavity dispersion compensation results in near-transform-limited red pulses with durations down to 140 fs for 185 fs input pump pulses.

We report the generation of tunable GHz-repetition-rate femtosecond pulses in a synchronously-pumped optical parametric oscillator (SPOPO) with extended cavity length pumped by a 76 MHz Kerr-lens mode-locked Ti:sapphire laser. In a SPOPO based on periodically-poled LiNbO3, insertion of a prism pair for dispersion compensation internal to the linear cavity provides stable output pulse trains of up to 14th harmonic of pump repetition-rate (1064 MHz) with 70 mW of average power for 1.45 W of pump. Near-transform-limited pulses down to 216 fs are achieved with wide tunability across 1500-1540 nm by continuous detuning of the SPOPO cavity delay over 8 microm.