We have developed a longitudinally excited CO2 laser (wavelength: 10.6 μm) with controllable laser parameters such as a laser pulse shape. A CO2 laser is absorbed at a glass surface due to the high absorption of glass materials. CO2 laser processing is a thermal process, and thermal effects such as cracks and HAZ occur on the glass surface. Thermal effects depend on not only the laser irradiation conditions but also glass materials. There are various types of glass having different physical constants related to heat, such as the thermal expansion coefficient and the softening point. Six types of glass, namely, crown glass, soda-lime glass, borosilicate glass, low-expansion borosilicate glass, alkali-free glass and synthetic quartz glass were irradiated with various types of short CO2 laser pulses. In the conditions of this experiment, no cracks occurred in any material. The size of the HAZ depended on the glass material, while the cutting depth was independent of the glass material.
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