BaGa_(4)Se_(7)与KTiOAsO_(4)光参量振荡输出3.5μm激光性能对比

Comparison of output 3.5μm laser properties by optical parametric oscillation of BaGa_(4)Se_(7) and KTiOAsO_(4)

为对比新型非线性晶体BaGa_(4)Se_(7)(简称BGSe)和成熟商用非线性晶体KTiOAsO_(4)(简称KTA)所输出的中红外激光性能,使用1.06μm激光泵浦BGSe(56.3°,0°,type-Ⅰ)和KTA(90°,0°,type-Ⅱ-A)输出3.5μm激光。在泵浦光波长为1064 nm、脉宽为13 ns、光斑直径为4 mm、光参量振荡腔长为90 mm的条件下,实验测得KTA(L=20 mm)和BGSe(L=15 mm)的泵浦振荡阈值分别为52.6 mJ(理论值为46.11 mJ)和20.6 mJ(理论值为18.32 mJ);BGSe输出波长与温度的变化率Δλ_(2)/ΔT为3.20 nm/℃(理论值为2.49 nm/℃),KTA的Δλ_(2)/ΔT为0.073 nm/℃(理论值为0.077 nm/℃);实验测得BGSe的输出线宽为4.71 nm,KTA为2.45 nm。BGSe和KTA的泵浦阈值和温度调谐在理论和实验上吻合得较好,且结果表明:BGSe在这两个方面优于KTA;但KTA在输出窄线宽方面优于BGSe晶体。实验结果表明,BGSe是一种具有广泛应用前景的中远红外非线性晶体。

In order to compare the mid infrared laser performance output by the new nonlinear crystal BaGa_(4)Se_(7)(BGSe)and the mature commercial nonlinear crystal KTiOAsO_(4)(KTA),the 1.06μm laser was used to pump BGSe(56.3°,0°,type-Ⅰ)and KTA(90°,0°,type-Ⅱ-A)to output 3.5μm laser.The pump oscillation threshold of KTA and BGSe was 52.6 mJ(the theoretical value was 46.11 mJ)and 20.6 mJ(the theoretical value was 18.32 mJ)respectively when the pump wavelength was 1064 nm,the pulse width was 13 ns,the beam diameter was 4 mm and theoptical parametric oscillator,cavity length was 90 mm.The Δλ_(2)/ΔT of BGSe and KTA was 3.20 nm/℃(the theoretical value was 2.49 nm/℃)and 0.073 nm/℃(the theoretical value was 0.077 nm/℃).The output linewidth of BGSe and KTA was 4.71 nm and 2.45 nm respectively.The experimental results of the pump oscillation threshold and the temperature tuning range fit the theoretical simulation well,and the results show that BGSe is better than KTA in these two aspects.But the output linewidth of KTA is narrower than that of BGSe.The experimental results indicated that BGSe is a mid-to far-infrared nonlinear crystal with wide applications.