Laser processing of glass plates using nanosecond lasers with three wavelengths

In this paper, a series of experiments of drilling holes and slotting micro-channels on the 1 mm-thick BK7 or 1.1 mmthick B270 glass substrates are introduced by employing three types of Q-switched lasers with the wavelength of 1064, 355, and 266 nm. Firstly, by smearing the solution of NiSO4∙6H2O on the front surface of BK7 glass plates, we successfully realized drilling holes on the glass substrates by employing a 1064 nm fundamental Nd:YAG laser. Then, we also carried out the experiments of drilling holes by utilizing a normal third-harmonic-generation (THG) 355 nm Nd:YAG laser and a 266 nm FHG (forth-harmonic-generation) laser. It can be found that the diameters of drilled holes by utilizing a 355 nm laser are larger than those by utilizing a 266 nm laser, and the holes with both two wavelengths lasers did not change a lot when the exposure time of lasers was increased from 0.5 s to 30 s. Finally, the experiments of slotting micro-channels on B270 glass plates were undertaken by utilizing both a 355 nm laser and a 266 nm laser. It has been found that the cracks around slotted micro-channels become lesser when the moving speeds are increased for both experiments. The channel widths of using the 355 nm laser are around 10 times smaller than those of using the 266 nm laser. As a conclusion, among three kinds of lasers, the 355 nm laser may be the most suitable type for the glass micro-processing with high precision in practice.