Cutting plano-convex cylindrical lenses with ultrafast Bessel laser beam

While micro-cylindrical lenses are used in a wide variety of applications and are a core optical component in lasers and Light Detection and Ranging (LiDAR), etc. They are extremely difficult to cut. In this research, the peak power and ultrafast pulse of an ultrafast laser, as well as the long focal depth of the Bessel beam, were employed to make the Bessel beam incident from the bottom plane of a micro-cylindrical lenses, to ultimately produce a modified surface inside the lenses. The modified micro-cylindrical lenses can then absorb CO₂ laser energy with a wavelength of 10.6 μm and generate high thermal tension stress via the high rate of absorption rate of the CO₂ laser by the glass material, after this can be separated along the modified surface. Experimental results demonstrate that the factors affecting the cutting quality are primarily the laser incidence surface, the single-pulse energy, and the pulse modification spacing. Via the use of this method, the separation of a micro-cylindrical lens made of BK7 glass with R = 2 mm, F = 3.87 mm, and a width of 3 mm was successfully achieved. Furthermore, the maximum cutting speed reached 500 mm/s with a cut section roughness of 530 nm without any chipping or micro-cracking, thereby achieving good cutting quality and providing an effective method for the efficient cutting of micro-cylindrical lenses.