Femtosecond-laser fabrication of cyclic structures in the bulk of transparent dielectrics
Femtosecond-laser fabrication of cyclic structures in the bulk of transparent dielectrics
复制标题
飞秒激光在透明电介质中制造环状结构
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
A. Obidin
中科院分区：
文献类型：
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作者：
S. Vartapetov;D. Ganin;K. Lapshin;A. Obidin
我们报道了在将飞秒激光脉冲聚焦到透明材料体积的条件下，发展精密微加工技术的实验结果，这在眼科生物材料的加工中尤其重要。当样品扫描速度与FS脉冲重复频率之间存在一定的关系时，被激光辐射破坏的区域沿光轴向物镜方向移动，并在样品内部形成循环图案，确定了微加工这一特殊区域的实施条件和一些特征。认为引起损伤区域移动的主要原因是前一次脉冲产生的腔体边界附近材料密度和微观结构的变化引起折射率的改变和损伤阈值的降低。将上述研究结果应用于晶体、玻璃和聚合物的精密切割技术。在此条件下，可获得最佳质量的切削面，消除了循环区域的出现。在聚碳酸酯、聚甲基丙烯酸甲酯和熔融二氧化硅样品中，获得了沿激光方向长宽比大于200的圆柱形空腔和垂直于激光方向的直径的微毛细管。
We report the results of the experiments on developing precision micromachining technology, obtained under the conditions of focusing the pulses of a femtosecond (FS) laser into the volume of a transparent material, which is important, particularly, in the processing of biomaterials in ophthalmology. The implementation conditions and some characteristic features of the special regime of micromachining are determined, when at a definite relation between the sample scanning velocity and the repetition rate of FS pulses the region, destroyed by the laser radiation, is shifted along the optical axis towards the objective and back, forming cyclic patterns inside the sample. It is supposed that the main causes of the damage region shift are the induced modification of the refractive index and the reduction of the damage threshold due to the change in the material density and structure in the microscopic domain, adjacent to the boundary of the cavity produced by the previous pulse. The results of the performed study with the above regime taken into account were used in the technology of precision cutting of crystals, glasses and polymers. The best quality of the cut surface is achieved under the conditions, eliminating the appearance of the cyclic regime. In the samples of polycarbonate, polymethyl methacrylate and fused silica the cylindrical cavities were obtained with the aspect ratio higher than 200, directed along the laser beam, and microcapillaries with the diameter in the direction, perpendicular to this beam.