RESUMEN
A high-peak-power, widely tunable range long-wave infrared optical parametric oscillator (OPO) based on the BaGa4Se7 (BGSe) crystal is demonstrated in this Letter. Pumped by a 1064â nm Nd:YAG laser, a high-peak-power of 0.15â MW was achieved at 9.8â µm with a pulse width of 5.0â ns. At 11.0â µm, a high beam quality of M2x = 4.1 and M2y = 3.3 was achieved. By rotating the BGSe crystal, a broad tuning range of 6.7-13.9â µm was realized. Furthermore, a theoretical analysis was conducted to elucidate the reasons behind the improvement in beam quality in the x-direction as the wavelength of the idler wave increases.
RESUMEN
Nonlinear optical coefficients are important parameters for nonlinear optical crystals. Based on the previously disclosed BaGa4Se7 crystal coefficients, the optimum phase-matching direction with the largest effective nonlinear optical coefficient appears in the second octant (90∘<θ<180∘, 0∘<Ï<90∘). In this study, a recalibration was performed using the second-harmonic-generation method, and it was confirmed that the optimum phase-matching direction of the BaGa4Se7 crystal is located in its XZ principal plane (Ï=0∘). Therefore, this study will serve as a good reference for future applications of this excellent crystal.