长焦深、高分辨激光加工聚焦透镜

Laser Processing Lens of Long Focal Depth and High Resolution

受限于传统激光加工透镜焦深与焦斑大小的矛盾关系,分辨率与加工深度很难同时获得提升。提出一种通过对不同焦距的菲涅耳透镜相位采样组合形成长焦深、高分辨激光加工聚焦透镜的设计方法。针对10.6μm的激光加工波长,采用自编的程序设计了一个通光口径为11mm、中心焦距为47mm的激光纸张打孔透镜,并开展了相应的实验加工与测试。结果表明,该透镜与具有相同口径和焦距的传统透镜相比,焦深增加了2倍,并且在整个焦深范围内焦斑尺寸保持着与普通透镜相近的分辨率。该透镜实现简单,为大深度、高分辨的激光加工提供了可行的途径,在激光加工领域有较好的应用前景。

Limited by the contrary relationship of the focal depth and the focal size, it is hard to enlarge the fabrication depth while keeping high resolution for laser processing. To solve this problem, a design method for realizing Fresnel lens with long focal depth and small focal size by phase sampling and combination is proposed. A laser processing lens for drilling holes on paper with aperture of 11 mm and center focal length of 47 mm, working at the wavelength of 10. 6 μm, is designed by using a homemade program. Then it is fabricated and tested. The experiment results show that, compared with traditional lens with the same aperture, this lens has a 2 times longer focal depth, and the focal size is similar to that of the traditional lens along the entire focal depth. This lens is simple to realize and it provides a feasible way to achieve long focal depth and high resolution synchronously. The advantages make it with great application potential in the field of laser processing.