Tunability extension and pulse shortening by using a noncollinear configuration in a green-pumped BiB ₃ O ₆ femtosecond optical parametric oscillator

We report a noncollinear (NCL), high-power, synchronously pumped femtosecond optical parametric oscillator (OPO) based on type I (<i>o → e + e</i>) phase-matching (PM) inside the <i>yz</i> 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 (<i>xz</i> and <i>yz</i>) of the biaxial BiBO crystal in the collinear PM geometry, to only one optical plane of <i>yz</i>, and 2) considerable shortening of the produced signal pulses (down to 33 fs at 670 nm) across the tuning range.