High-precision polishing of laser-engraved complex profiles using femtosecond laser bursts

This study presents an optimized approach for high-quality fabrication and finishing of complex profiles using ultra-short laser pulses in single pulse and burst mode emission. By leveraging a femtosecond laser at 1030 nm with a 280 fs pulse duration, the method combines single pulses with pulse trains of up to 20 pulses per burst (PPB) at an intra-burst repetition rate of 41.6 MHz. Experimental results show a significant reduction in final surface roughness, achieving an S a below 100 nm while preserving underlying laser-engraved microstructures. Comparative analysis with non-burst operation reveals a threefold improvement in surface quality after process optimization, highlighting the potential of burst-mode femtosecond laser polishing for applications requiring high precision and minimal structural alteration of original laser-engraved structures. • Burst mode femtosecond pulses precisely control melting in metallic substrates. • Surface roughness reduction of 50%–60% achieved for various substrates. • Significant surface roughness reduction achieved, reaching S a below 100 nm. • Method preserves microstructure on complex geometries during processing.