全固态561nm倍频激光器研究

Research on 561 nm Frequency-Double All-Solid-State Laser

报道了利用激光二极管端面抽运Nd∶YAG晶体,通过LBO非线性晶体腔内倍频实现的561nm激光输出。LBO晶体尺寸为2mm×2mm×10mm,采用Ⅰ类相位匹配切割。抽运功率为5W时,561nm的最大输出功率为123mW,此时的光-光转换效率为2.46%。实验中发现激光器很容易同时出现556nm及558nm倍频光。从非线性转换效率对基频光振荡的影响角度出发,分析了1112nm与1116nm谱线起振的原因。作为对比,利用允许角范围小的KTP作为倍频晶体进行了同样的实验,KTP晶体的尺寸为2mm×2mm×8mm,采用Ⅱ类相位匹配切割。实验结果显示,在KTP晶体倍频情况下,激光器很容易实现561nm单谱线激光输出。实验结果与理论分析相一致。

561 nm laser output is achieved from LBO intra-cavity frequency doubling of a laser in which Nd： YAG is end-pumped by LD. Using the 2 mm× 2 mm× 10 mm LBO crystal with type- l phase matching cutting, the 561 nm laser output power is 123 mW when the pump power is 5 W. The conversion efficiency of 2.46% is obtained. The frequency-doubled light waves of 556 nm and 558 nm easily appear in experiment. From the influence of nonlinear conversion efficiency on fundamental-frequency light oscillation, the reason of 1112 nm and 1116 nm line oscillation is analyzed. As a contrast, we carry out the same experiment using a 2 mm× 2 mm× 8 mm KTP crystal with type-Ⅱ phase matching cutting. Results show that the laser is easy to realized 561 nm single spectral-line laser. The experimental results and theoretical analysis are consistent with each other.