Single-shot high-aspect-ratio drilling of transparent dielectrics using an orthogonal dual-USPL configuration

Transparent dielectrics are essential in advanced photonic, electronic, and medical devices owing to their excellent properties, but these very properties also make efficient micromachining difficult, particularly for high-aspect-ratio deep-hole fabrication. Here, we demonstrate a dual-beam approach that enables 153-µm-deep hole drilling within an effective processing time of 50 ps. In this scheme, a high-angle Bessel beam generates a highly absorptive filament, while a perpendicular, cylindrically focused pulse delivers energy to the filament vicinity. Compared with recent GHz Bessel-burst drilling, which typically relies on multiple pulses separated by several hundred picoseconds and therefore requires a total processing window on the order of nanoseconds, the present approach achieves analogous filament-assisted deep drilling in a compressed temporal window. This result highlights the potential of the proposed scheme as a new strategy for single-shot, high-aspect-ratio micromachining of transparent dielectrics and may provide a basis for future improvements in practical processing throughput through further development of system-level implementation strategies.