Micromachining of at cut quartz using 50 femtosecond laser pulses

Slots are micromachined in 75 µm thick AT cut crystalline quartz samples using 50 femtosecond laser pulses in a vacuum of 10 mTorr. The processed area is examined by optical and scanning electron microscope to determine the cut quality at the laser entrance and exit sides and also depth of cuts. Cuts with a high quality laser entrance side without microcracking could be obtained for fluence ranges from 2.5-13 J/cm² while microcracking around the cuts is observed at 16 J/cm². Damage on the exit side of the sample was observed for fluences above 2.5 J/cm² within a distance of 50 µm from the center of the cut and running parallel to the cut. This may be related to stress developed during cutting.