Glass is a very much different material at different wavelengths. For CO2 lasers glass absorbs all the energy in a thin surface level, which leads to uncontrolled cracking. This practically prevents larger adoption of CO2 lasers. In contrast, for the solid-state lasers operating at 532 nm glass is almost transparent. Here the challenge is opposite – to keep the energy inside the material. Eventually, there are lasers and lasers.
To understand differences and adjust expectations accordingly, we need to know the physics behind interaction of lasers with glass. The thermal stress technique using CO2 lasers was announced to bring the breakthrough about ten years ago. However, lately the focus has shifted towards the picosecond pulsed solid-state lasers. Few years ago Coherent has introduced the SmartCleave method, which utilizes self-focusing of light within the glass. An alternative Nanoperforation technique developed by Corning also uses solid-state lasers. Because of the physics of the process, for both, post-processing is needed to remove stresses and smoothen the edge. In contrast, CO2 lasers always provide transparent and stress-free edge.
Processing by solid-state lasers is becoming popular for drilling, cutting closed shapes and thin display glass cutting, where it’s used in combination with CO2 lasers. However, it’s not applicable for cutting of thick float glass and will never work at elevated temperatures.
Our new nanosecond-pulsed CO2 laser has potential to revolutionize the industry. It can cut any glass thickness, incl. laminated glass, producing transparent, stress-free edge, and enabling clean and sustainable glass processing.