Sep 18, 2020
As we all know, ultrafast lasers refer to pulsed lasers whose output laser pulse width is in the picosecond (10-12 seconds) level or less than the picosecond level, with extremely high peak power.
For transparent materials such as glass, when the ultra-high peak power laser is focused inside the transparent material, the nonlinear polarization caused by the light propagation inside the material changes the light propagation characteristics, causing the beam to appear self-focusing (Wavefront focusing). Due to the extremely high peak power of the ultrafast laser, the pulse is continuously focused in the glass and transmitted all the way down to the inside of the material without divergence until the laser energy is insufficient to continue to support the self-focusing phenomenon. At this point, the place where the laser has been transmitted leaves a trace like a thread (only a few microns in diameter). Connect these threads and apply stress to them, and the glass will split along the threads.
This is the result of the glass being modified by the laser, and the modified glass has different properties from the original. And this processing method also ensures that the processing process will not affect the surrounding materials in the space involved, so as to achieve the "super fine" processing.
In addition, non-contact processing can also avoid problems such as chipping and cracking in traditional machining methods. It has high precision, no micro-cracks, broken or fragmented problems, high edge fracture resistance, and no need for washing, grinding, polishing, etc. The secondary manufacturing cost and other advantages, while reducing the cost, greatly improve the workpiece yield and processing efficiency.