LD泵浦腔内倍频Nd：YAG／LBo蓝光473nm激光器的低噪声运转

LD pumped intracavity frequency doubling 473 nm Nd:YAG/LBO laser with low noise operation

激光二极管(LD)泵浦腔内倍频Nd:YAG/LBO蓝光473 nm激光器在不加入腔内特殊元件的情况下,倍频输出功率往往具有很大的高频噪声,即所谓的'蓝光问题',这很大程度上限制了473 nm蓝色激光的应用。为了降低该激光器件倍频输出功率的高频噪声,采用了提高腔内基频光循环强度和缩短激光晶体以减小准三能级激光系统再吸收损耗的方法来实现473 nm激光器的低噪声运转。实验中利用两个2 WLD耦合作为泵浦源及1.0 mm厚的Nd:YAG材料作为激光晶体,在利用10 mm长LBO材料作为倍频晶体的情况下,获得了输出功率为195 mW的具有低噪声特性的473 nm蓝光激光运转。实验结果表明,倍频输出功率(峰-峰)/平均值<1%,激光输出在1 h内没有激光跳变现象,并且无需在腔内引入其它元件。

The larger amplitude fluctuations of high-frequency output power in a laser-diode pumped intraeavity frequency doubled 473 nm Nd. YAG/LBO blue laser are observed without special intraeavity elements,which is called the ＂blue problem＂, and it seriously restricts the development and applications of the 473 nm blue laser in many fields. To reduce the high-frequency noise of frequency doubling output of the blue laser, a method of decreasing reabsorption losses in quasi-three-level laser system was presented by increasing intraeavity circulating intensity of fundamental wave and by decreasing length of laser crystal. In experiment, using two 2 W I.D as pumped source and a 1.0 mm Nd：YAG crystal as laser crystal,the blue laser with output power of 195 mW and low noise operation was obtained by intraeavity doubling with a 10 mm LBO. The experimental results show that the （peak-peak）/mean value of frequency doubling output power of the blue laser is less than 1%. The laser output is no hopping in 1 h and also no any intraeavity elements are introduced to control the longitudinal mode.