High-speed microgroove processing of glass by expanding the high-temperature region formed by transient and selective laser absorption.

Microgroove processing of glass is important in many fields, however, it is difficult to achieve the processing with a high speed. In this study, we developed a novel method for the high-speed microgroove processing of glass using two types of lasers, namely a femtosecond laser and a near-infrared continuous-wave (CW) laser. A single femtosecond laser pulse was initially focused on the surface of the material, enabling the area to absorb the CW laser, which is otherwise not absorbed by the glass. The CW laser was then scanned along the material surface, expanding the machined hole to form a groove. The resulting grooves, with a width of approximately 10 µm and depths of up to 350 µm, can be machined with a scanning speed of up to 200 mm/s, 25 times faster than conventional methods. This method exhibits the potential to improve the industrial application of fast laser microprocessing of glass.