Micro- and nanoparticle generation during nanosecond laser ablation: correlation between mass and optical emissions

Area of Science:

• Materials Science
• Laser-Matter Interaction
• Surface Engineering

Background:

• Nanosecond laser ablation is crucial for material processing.
• Understanding particulate emission is key to controlling nanoparticle synthesis and minimizing debris.
• Gold's unique properties make it a relevant target for ablation studies.

Purpose of the Study:

• To investigate particulate emission during nanosecond ablation of gold targets.
• To identify distinct mass removal mechanisms under varying experimental conditions.
• To correlate atomic emission spectra and particle morphology with ablation processes.

Main Methods:

• Performed nanosecond laser ablation on gold targets at fluences of 10-100 Jcm⁻² and vacuum levels from 0.05-750 Torr.
• Acquired atomic emission spectra during ablation.
• Characterized particle spatial distribution using scanning electron microscopy (SEM).

Main Results:

• Identified four distinct mass removal mechanisms by analyzing emission spectra and SEM data in conjunction with theoretical models.
• Observed that atomic emission lines (presence, shape, intensity) are indicative of nanoparticle formation.
• Linked fluctuations in the emission signal across multiple laser shots to the generation of microscopic debris.

Conclusions:

• The study elucidates the complex mechanisms governing particulate emission in gold ablation.
• Atomic emission spectroscopy and SEM provide complementary insights into nanoparticle formation and debris generation.
• Findings contribute to optimizing laser ablation processes for controlled material synthesis and surface modification.