Ultrabroadband few-cycle infrared pulse generation from a noncollinear optical parametric amplifier based on bulk niobate crystals

We describe a near-IR two-stage noncollinear optical parametric amplifier (NOPA) pumped at 800 nm that employs bulk congruent lithium niobate [LiNbO3 (c-LNB)] and bulk potassium niobate [KNbO3 (KNB)] crystals. Noncollinear phase matching in these materials allows for generation of pulses as broad as 2900 cm−1 (∼78 THz) centered in the near-IR at ∼1300 nm. In the particular geometry described here, the LNB crystal amplifies the white-light seed continuum, and the KNB crystal further amplifies the broadband near-IR pulses. Use of pulse-front matching at both nonlinear optical crystals allows for improvement of the spatiotemporal profile of the amplified ultrabroadband signal pulses and their compression to ≤22 fs. Because of the relatively high nonlinear coefficients of these crystals, we achieve overall amplification efficiencies >7% in two consecutive NOPA stages. © 2013 Optical Society of America OCIS codes: (160.3730) Lithium niobate; (190.4410) Nonlinear optics, parametric processes; (190.7110) Ultrafast nonlinear optics; (190.4223) Nonlinear wave mixing; (320.7110) Ultrafast nonlinear optics. http://dx.doi.org/10.1364/JOSAB.30.002075