LIBS using dual- and ultra-short laser pulses.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique.
• Dual-pulse excitation can enhance LIBS signal intensity.
• The effect of different laser pulse durations on LIBS is an area of ongoing research.

Purpose of the Study:

• To investigate dual-pulse laser-induced breakdown spectroscopy (LIBS) enhancement for copper, brass, and steel using nanosecond (ns) laser excitation.
• To explore the effects of picosecond (ps) and femtosecond (fs) laser excitation on single-pulse LIBS.
• To evaluate the utility of a dual-pulse fiber-optic LIBS probe.

Main Methods:

• Utilized nanosecond (ns), picosecond (ps), and femtosecond (fs) laser pulses for LIBS.
• Employed pre-ablation dual-pulse excitation.
• Investigated near-collinear dual-pulse fiber-optic probe.
• Analyzed LIBS spectra and atomic emission decay.
• Tested high pulse rates up to 1,000 Hz with non-gated detection.

Main Results:

• Observed significant LIBS enhancement for copper, brass, and steel with dual-pulse ns excitation, though matrix-dependent.
• Discovered that ps and fs laser pulses yield lower background signals compared to ns pulses.
• Noted rapid atomic emission decay with ps and fs pulses.
• Demonstrated effective non-gated detection due to low backgrounds with ps/fs pulses.
• Confirmed the effectiveness of high pulse rates (up to 1,000 Hz) for signal enhancement.
• Showcased the utility of a dual-pulse fiber-optic probe for enhanced LIBS.

Conclusions:

• Dual-pulse LIBS offers significant enhancement across different metallic matrices.
• Ultrashort laser pulses (ps, fs) provide advantages in reduced background and faster plasma dynamics for LIBS.
• Non-gated detection and high pulse rates are viable for ps/fs LIBS.
• Fiber-optic probes are suitable for enhanced dual-pulse LIBS applications.