Tunability extension and pulse shortening by using a noncollinear configuration in a green-pumped BiB₃O₆ femtosecond...

We report a noncollinear (NCL), high-power, synchronously pumped femtosecond optical parametric oscillator (OPO) based on type I (o → e + e) phase-matching (PM) inside the yz optical plane of BiB₃O₆ (BiBO) crystal. By the application of NCL PM geometry for the parametric interaction, two important goals have been achieved: 1) simplifying the wavelength tuning by transferring the full tunability (620-1030 nm for signal and 1030-3050 nm for idler) from two optical planes (xz and yz) of the biaxial BiBO crystal in the collinear PM geometry, to only one optical plane of yz, and 2) considerable shortening of the produced signal pulses (down to 33 fs at 670 nm) across the tuning range.