Debris-Free, Zero Taper Cutting of BOROFLOAT 33 Glass Using a Femtosecond Bessel Laser Beam
Z-Q. Li, J-L. Wang, X-F. Wang, O. Allegre, W. Guo, W-Y. Gao, Y. Xue and Lin Li
Owing to nonlinear absorption, ultra-short pulse lasers can be used to modify the properties of bulk transparent materials. In this paper, an 800 nm femtosecond laser Bessel beam was used to induce nonlinear filamentation inside a bulk BOROFLOAT 33 borosilicate glass sheet, followed by mechanical cleavage. The effects of scanning speed on the cleavage force and surface roughness were analysed. By increasing the number of lasers passes over the test piece, the cleavage force was reduced while the sidewall surface roughness was increased. By optimizing the process parameters, straight and curved cuts have been achieved free from debris and crack, with a zero taper a surface roughness around 550 nm Ra.
Keywords: Ti:Sapphire femtosecond laser, BOROFLOAT 33 glass, surface roughness, Bessel beam, filament, scanning passes, bending force