Calculation of phase-matching angles and effective nonlinear coefficients of BaGa4Se7 crystals

The optimal phase-matching angles and the maximum distribution of effective NLO coefficient (deff) of BaGa4Se7 are calculated for the first time. When the range of the idler light wavelength is 2–12 μm and the pump light wavelength is 1.06 μm, the optimal phase-matching angles θ,∅ are (117°-29.3°, 6°-33.55°) and (73°-37.9°, 37.45°-21.2°) for type-I and type-II(B), respectively. The maximum | deff | from type-I is larger than type-II(B) when the wavelength range of idler light is from 2 to 5 μm, and smaller than type-II(B) when the wavelength range of idler light is from 6 to 12 μm.