Laser-Induced Periodic Surface Structures in Polymers with Tailored Laser Fields

In this work, laser-induced periodic surface structures (LIPSS) are generated on the surface of thin films of poly(trimethylene terephthalate) (PTT) fabricated by spin coating on silicon. Previous studies have shown the appearance of LIPSS in this type of materials with femtosecond laser pulses in the near-infrared region of the spectrum, despite the extremely low absorption of the polymer. The present work consists of an exploration of the effect of adding complexity to the femtosecond laser fields employed for irradiation. Changes in the repetition rate of the pulse train, the pulse duration, and the pulse temporal chirp are explored, and conditions for optimum LIPSS formation are identified. The effects of these modifications on the polymer surface topography, assessed by atomic force microscopy, are described and discussed. Periodic surface structures in the sub-micron range have been generated on the surface of a polymeric thin film deposited on Si by irradiation with trains of near-infrared, ultrashort laser pulses. The effects of varying properties of the train of pulses (inter-pulse delay, pulse duration, and frequency chirp) on the characteristics of the laser-induced surface topography have been investigated.image (c) 2023 WILEY-VCH GmbH