High average power, widely tunable femtosecond laser source from red to mid-infrared based on an Yb-fiber-laser-pumped optical parametric oscillator

We report on the highly efficient generation of widely tunable femtosecond pulses based on intracavity second harmonic generation (SHG) and sum frequency generation (SFG) in a MgO-doped periodically poled LiNbO3 optical parametric oscillator (OPO), which is pumped by a Yb-doped large-mode-area photonics crystal fiber femtosecond laser. Red and near infrared from intracavity SHG and SFG and infrared signals were directly obtained from the OPO. A 2 mm beta - BaB2O4 is applied for Type I (oo -> e) intracavity SHG and SFG, and then femtosecond laser pulses over 610 nm similar to 668 nm from SFG and 716 nm similar to 970 nm from SHG are obtained with high efficiency. In addition, the oscillator simultaneously generates signal and idler femtosecond pulses over 1450 nm similar to 2200 nm and 2250 nm similar to 4000 nm, respectively. (C) 2013 Optical Society of America