Simple Nd:YAG laser generates vector and vortex beam
Simple Nd:YAG laser generates vector and vortex beam
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DOI：
10.3788/col201513.031405
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发表时间：
2015-03
影响因子：
3.5
通讯作者：
Zhiqiang Fang;Yao Yao-Yao;K. Xia;Jian-lang Li
中科院分区：
文献类型：
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作者：
Zhiqiang Fang;Yao Yao-Yao;K. Xia;Jian-lang Li
本文报道一种简单的Nd：YAG激光器，它能输出具有螺旋波阵面的径向偏振光束。激光谐振腔由一片激光晶体和一个平面输出耦合器组成，腔内没有附加偏振分量，泵浦光通过离焦耦合进入多模光纤，形成环形轮廓。对于连续波（CW）操作，激光器发射径向偏振涡旋光束，并且观察到，当输出耦合器稍微倾斜时，激光束的螺旋波前从右旋切换到左旋。对于腔内插入Cr ~（4+）：YAG可饱和吸收体的调Q操作，我们获得了具有左旋螺旋波前的径向偏振输出。在泵浦功率大于4.5W时，通过倾斜激光晶体，激光输出转为方位偏振，并保持了激光束的左旋螺旋波前。
We report a simple Nd:YAG laser that emits radially polarized beam with helical wavefront. The laser cavity consists of a piece of laser crystal and a plane output coupler, and there is no additional polarization component inside it. The pump light is converted into annular profile through de-focal coupling into a multi-mode fiber. For the continuous-wave (CW) operation, the laser emits radially polarized vortex beam, and it is observed that the helical wavefront of the laser beam is switched from right handedness to left handedness when the output coupler is tilted slightly. For the Q-switched operation under the insertion of a Cr4+:YAG saturable absorber inside the cavity, we obtain radially polarized outputs with left-handedness helical wavefront. By tilting the laser crystal slightly, the laser output switches to azimuthal polarization at pump power larger than 4.5 W and left-handedness helical wavefront of laser beam is preserved.