Periodic Surface Structuring of Copper with Spherical and Cylindrical Lenses

Area of Science:

• Materials Science
• Laser Physics
• Surface Engineering

Background:

• Femtosecond laser surface structuring is crucial for advanced material applications.
• Improving processing efficiency and controlling surface morphology are key challenges.
• Cylindrical lenses offer potential advantages over spherical lenses for laser-based surface modification.

Purpose of the Study:

• To compare the surface structures generated by spherical and cylindrical lenses using femtosecond laser pulses on copper.
• To elucidate the similarities and differences in surface morphology produced by these two focusing configurations.
• To investigate the effect of scanning parameters on surface structuring with a cylindrical lens.

Main Methods:

• Surface analysis of copper targets after femtosecond laser irradiation (≈180 fs, 1030 nm and 515 nm).
• Utilizing both spherical and cylindrical lenses for beam focusing.
• Varying scanning parameters, including hatch distance, with a cylindrical lens.

Main Results:

• Spherical lenses produced micron-sized parallel channels, subwavelength ripples, and nanoparticles.
• Cylindrical lenses resulted in surfaces with ripples and nanoparticles, but negligible micro-channels.
• Hatch distance significantly influenced surface morphology, creating distinct dark and bright bands due to nanoparticle redeposition variations.

Conclusions:

• The choice between spherical and cylindrical lenses significantly impacts femtosecond laser-induced surface morphology on copper.
• Cylindrical lenses are effective for creating ripple and nanoparticle-based surfaces without micro-channels.
• Understanding the influence of scanning parameters is vital for optimizing large-area surface structuring with cylindrical lenses.