Grating structures are fabricated inside glass based on femtosecond laser parallel processing technology

Femtosecond laser single-focus scanning has the problem of low efficiency when manufacturing large-area structures. This paper proposes a multi-focus parallel processing method based on the weighted Gerchberg-Saxton (GS) algorithm. A multi-focus hologram was designed and loaded onto a spatial light modulator to achieve uniform energy distribution. The effects of repetition frequency, pro-cessing times and scanning speed on the morphology of microchannels were systematically studied, and the uniformity was all above 90%. Using the opti-mized process parameters, a grating structure with a cross-sectional width of approximately 29.315 μm was fabricated inside the glass by the three-focal parallel process. Compared with single-focus scanning, this method triples the efficiency while maintaining high quality, providing a promising path for the manufacturing of scalable photonic devices.