飞秒激光多次聚焦在并行加工中的应用

Application of femtosecond laser multi-focusing to parallel fabrication

提出了利用飞秒激光的多次聚焦现象进行微光学器件并行加工的方法。通过实验总结了光强和聚焦深度对该方法的影响规律，并实现了用该方法并行加工多个微光波导。对多个微光波导的间距实现了控制，其间距范围为2～5μm。将并行加工出的光波导与单个焦点加工出的光波导做了对比，并行加工出的光波导形貌上比较接近单个焦点加工出的光波导，但其传输性能还有一定的差距。用超强光引起的自聚焦对这种多次聚焦做了理论解释，并且针对光强和聚焦深度对多次聚焦的影响做了进一步的理论分析。结果表明，这种方法相对以往的并行加工，实现简单，对加工结果的控制相对灵活。该方法利用的是超强激光特有的非线性现象，为飞秒激光的高效率加工开拓了方向。

A parallel fabrication method of micro-optic devices by multi-focusing fs laser was presented. The influence of laser intensity and focusing depth on the experiments was studied. Multiple micro-waveguides were fabricated by the parallel method and the space between parallel microwaveguides was controlled in 2-5μm. The waveguides fabricated by parallel method were compared with that by single fusing method, the results show that both kinds of waveguides have the same shape,but the waveguides fabricated by parallel method are inferior to the latter in transmission per- formance. The multi-focusing was interpreted with the phenomena of self-focusing induced by ultra powerful laser, and the effects of laser intensity and focus depth on the multi-focusing were theoretically analyzed. Experimental results show that this method has advantage in flexible control and easy operation compared with other parallel methods.