Multiple laser parametric study of fiber-laser-induced breakdown spectroscopy.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Laser-Material Interactions

Background:

• Laser-induced breakdown spectrometry (LIBS) is a powerful technique for elemental analysis.
• Optimizing LIBS performance requires understanding the interplay of various laser parameters.
• Previous studies have explored individual parameters, but an integrated investigation is needed.

Purpose of the Study:

• To comprehensively investigate the effects of pulse energy, pulse width, and repetition rate on LIBS performance.
• To determine optimal laser parameters for enhanced sensitivity and improved limit of detection (LOD).
• To elucidate the underlying mechanisms influencing signal intensity and ablation characteristics.

Main Methods:

• Systematic variation of pulse energy (0-0.8 mJ), pulse width (2-500 ns), and repetition rate (1 Hz-4 MHz).
• Analysis of aluminum samples using laser-induced breakdown spectrometry.
• Quantification of signal enhancement, electron density, ablation threshold, and limit of detection (LOD).

Main Results:

• Increased pulse energy significantly elevated the signal.
• Longer pulse widths reduced electron density and ablation threshold, but slowed signal speed.
• A repetition rate threshold of approximately 200 Hz was found for signal enhancement, with higher rates (e.g., 20 kHz) yielding up to 29.0% sensitivity enhancement and 43.9% LOD improvement.

Conclusions:

• Optimal LIBS quantification is achieved by employing higher pulse energy, a moderate pulse width, and a higher repetition rate.
• The study demonstrates significant improvements in sensitivity and LOD, achieving detection down to tens of ppm.
• Findings provide crucial insights for optimizing LIBS protocols for various analytical applications.