Genesis of femtosecond-induced nanostructures on solid surfaces

Area of Science:

• Materials Science
• Laser-Matter Interaction
• Surface Engineering

Background:

• Laser-induced periodic surface structures (LIPSS) are a common phenomenon in laser-matter interaction.
• The formation mechanisms and evolution pathways of LIPSS are not fully understood.
• Controlling LIPSS is crucial for applications in optics, electronics, and nanotechnology.

Purpose of the Study:

• To investigate the initiation and evolution of LIPSS formation.
• To demonstrate the critical role of irradiation dose in determining LIPSS properties.
• To observe the complete evolution of LIPSS within a single irradiated spot.

Main Methods:

• Systematic variation of irradiation dose (fluence × number of pulses).
• In-situ observation of structural evolution within a single laser-irradiated spot.
• Microscopic analysis of surface morphology at different irradiation stages.

Main Results:

• Demonstrated a clear progression of structure formation with increasing irradiation dose.
• Observed the transition from random surface modifications to regular sub-wavelength ripples.
• Documented the coalescence into broader LIPSS and the formation of complex structures with deep craters due to ablation.

Conclusions:

• Irradiation dose is a critical parameter governing LIPSS morphology and evolution.
• A comprehensive pathway for LIPSS formation, from initial modification to complex structures, has been elucidated.
• The findings provide a foundation for precise control over laser-induced surface structuring.