Electro-optic and acousto-optic laser beam scanners
Electro-optic and acousto-optic laser beam scanners
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DOI：
10.1117/12.2212208
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
J. Heberle;P. Bechtold;J. Strauss;Michael Schmidt
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文献类型：
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作者：
J. Heberle;P. Bechtold;J. Strauss;Michael Schmidt
电光偏转器（EOD）和声光偏转器（AOD）基于激光在固态介质内的偏转。由于它们不包含任何移动部件，因此与传统上用于激光束偏转的机械扫描仪相比，它们具有优势。即使对于任意扫描路径，也可以实现高进给速率。在这项工作中，EOD和AOD的工作原理和特性。此外，与基于反射镜的机械偏转器在偏转角度、速度和精度方面的比较是在可分辨斑点和可分辨斑点的速率方面进行的。特别是，后者是高达一个数量级的EOD和AOD系统相比，传统的系统更高。进一步的特性，如响应时间，损伤阈值，效率和光束失真进行了讨论。固态激光束偏转器通常的特征在于小的偏转角但是高的角偏转速度。由于机械偏转器表现出相反的性质，因此机械扫描器与固态偏转器组合的布置提供了具有两种系统的益处的解决方案。由于平均功率在100 W以上、重复频率在MHz范围内的超短脉冲激光器已经存在了好几年，因此可以应用这种方法来充分利用它们的能力。因此，可以减少脉冲重叠，并且通过这种方式防止热影响区域，以提供适当的处理结果。
Electro-optical deflectors (EOD) and acousto-optical deflectors (AOD) are based on deflection of laser light within a solid state medium. As they do not contain any moving parts, they yield advantages compared to mechanical scanners which are conventionally used for laser beam deflection. Even for arbitrary scan paths high feed rates can be achieved. In this work the principles of operation and characteristic properties of EOD and AOD are presented. Additionally, a comparison to mirror based mechanical deflectors regarding deflection angles, speed and accuracy is made in terms of resolvable spots and the rate of resolvable spots. Especially, the latter one is up to one order of magnitude higher for EOD and AOD systems compared to conventional systems. Further characteristic properties such as response time, damage threshold, efficiency and beam distortions are discussed. Solid state laser beam deflectors are usually characterized by small deflection angles but high angular deflection velocities. As mechanical deflectors exhibit opposite properties an arrangement of a mechanical scanner combined with a solid state deflector provides a solution with the benefits of both systems. As ultrashort pulsed lasers with average power above 100 W and repetition rates in the MHz range have been available for several years this approach can be applied to fully exploit their capabilities. Thereby, pulse overlap can be reduced and by this means heat affected zones are prevented to provide proper processing results.