Controlled photothermal ablative processing of commercial polymers minimizing undesired thermal effects under high frequency femtosecond laser irradiation

• Published in: Optics and laser technology 2024-10, Vol.177, p.111069, Article 111069
• Main Authors: Bernabeu, A.P., Puerto, D., Ramirez, M.G., Nájar, G., Francés, J., Gallego, S., Márquez, A., Pascual, I., Beléndez, A.
• Format: Article
• Language: English
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2024.111069

•Three commercial polymers with different thermal properties (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) has been studied under λ = 515 nm femtosecond laser irradiation.•A photothermal model has allowed us to estimate the threshold frequencies of three different heat regimes observed experimentally (non-cumulative, cumulative and saturation).•Better performance has been observed in high frequency processing with greater uniformity and less debris.•The thermal characteristics of materials determine their behavior under femtosecond laser irradiation. The response of three commercial polymers (poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET) and polypropylene (PP)) with different thermal properties under high repetition rates (1 kHz-1 MHz) with femtosecond (450 fs) multi-pulse laser irradiation at λ = 515 nm (1.4 J/cm2) is reported resulting in a complete study with controlling the ablation depth and minimizing collateral thermal effects. Tunable ablation depth is achieved accurately by varying the repetition rate at a constant fluence. The results are compared to a photothermal model that aims at explaining the heat accumulation effect of successive pulses as a function of the repetition rate and predicts three different heat regimes (non-cumulative, cumulative and saturation). The threshold frequencies for each regime can be estimated from the model, providing control for selecting frequency values and thermal regimes. Thermal analyses are performed to characterize the materials, concluding that thermal parameters are vital for selecting optimal materials and laser processing parameters.