Wide acceptance bandwidth difference frequency generation in quasi-phase-matched LiNbO3

Difference frequency generation in quasi-phase-matched LiNbO3 is carried out using a Nd:YAG laser and a high power semiconductor laser. Operation at quasi-phase-matching degeneracy point results in an ultrawide 0.5 μm acceptance bandwidth. Crystal-rotation-free wavelength tuning of 4.0–4.5 μm, with 0.2 mW output power at 4.5 μm is achieved. Separately, a tuning range 3.0–5.5 μm is demonstrated with sample rotation and a Ti:Al2O3 laser.