全固态高输出功率单频Nd:YVO4/KTP激光器

利用光纤耦合输出的半导体激光器(LD)端面抽运Nd∶YVO4晶体,激光谐振腔采用四镜环形腔结构,通过KTP晶体内腔倍频,获得了高功率全固态连续单频绿光激光输出。根据临界相位匹配下椭圆高斯光束的倍频理论,通过旋转Nd∶YVO4晶体的方向选取合适的基频光偏振方向,使KTP晶体的走离角所在平面与谐振腔弧矢面平行,可提高内腔倍频转换效率。当抽运功率为20 W时,激光器最大单频绿光输出功率达4.8 W。作为对比,控制基频光偏振方向使KTP晶体的走离角所在平面与谐振腔子午面平行时,激光器最大单频绿光输出功率为4.1 W。对比两种情形下的实验结果,激光器的光-光转换效率从21.8%提高到25.5%。

All-Solid-State High-Efficiency High-Power Nd: YVO4/KTP Laser of Single-Frequency Operation

An all-solid-state single frequency Nd:YVO4/KTP laser with high efficiency and high power is reported, with fiber-coupled laser diode (LD) end-pumping Nd:YVO4 crystal, ring resonator consisting of four mirrors, and KTP crystal intracavity frequency doubling. Based on the frequency-doubling theory of elliptical Gaussian beam under conditions of critical phase mathcing, an improved intracavity frequency-doubling conversion efficiency is obtained by tuning the orientation of Nd:YVO4 crystal and choosing appropriate polarizing direction for fundermental frequency light to make the walk-off plane of KTP crystal paralle to the sagittal plane of cavity. The peak output power of single frequency green laser reaches to 4.8 W and the optical-optical conversion efficiency equals to 25.5%, when the pumping power is 20 W. In comparison, when the walk-off plane is perpendicular to the sagittal plane, the conversion efficiency is 21.8%, and the maximal single frequency green laser output power is 4.1 W.