Femtosecond laser processing of quartz wafers for precision cutting of tuning forks

In this work, femtosecond laser cutting of quartz wafers was demonstrated as an environmentally friendly alternative to the standard etching methods for production of sensitive sensor devices. The proposed approach employed milling channels for processing of the entire wafer thickness. The laser parameters examined for this procedure were the pulse energy, the number of scans and the channel width. Subsequent analysis of each channel focused on evaluating its depth, the angle of tapering, and the overall quality of the cut. The laser system operated at a central wavelength of 515 nm, delivering pulses with a temporal width of 390 femtoseconds. After identifying the optimal laser parameters for achieving the best channel quality through the wafer thickness (280 μm), the method was used to directly laser-cut quartz microresonators in a tuning-fork geometry. The resonant performance of laser-cut tuning forks was simulated and experimentally validated using a laser-vibrometer under photoacoustic excitation. The results matched standard quartz-tuning-fork behavior, with the junction quality between the body and prongs significantly impacting performance. This study confirms femtosecond laser cutting as an efficient, eco-friendly method for producing quartz micro-devices, enabling single prototype fabrication not achievable with conventional methods.