Ultra-low-energy and high-speed micro-laser-induced breakdown spectroscopy using GHz repetition rate pulses

TL;DR

This paper demonstrates high-speed micro-LIBS using GHz burst-mode laser pulses with ultra-low energies, enabling rapid and efficient material analysis with detailed plasma diagnostics.

Contribution

The study introduces a novel GHz repetition rate burst-mode laser system for micro-LIBS, achieving over 100 kHz speed with ultra-low pulse energies and detailed plasma characterization.

Findings

Achieved micro-LIBS at over 100 kHz with 10-200 nJ pulses.

Analyzed plasma parameters like electron temperature and density.

Studied effects of burst duration and energy on spectral emissions.

Abstract

Using GHz repetition rate pulses in burst mode has demonstrated numerous advantages for highly efficient material removal. In this work, we present high-speed (over 100 kHz) micro-laser-induced breakdown spectroscopy (micro-LIBS) with ultra-low pulse energies in the range of 10-200 nJ using our recently developed 2.8 GHz burst-mode Yb-doped fiber laser. We delivered 40 ps-long pulses to the sample with a beam diameter of about 18 microns. A systematic LIBS study was conducted on stainless steel (SS) at different burst durations and burst energies to study their effects on the optical emission spectrum. Finally, the electron temperature and electron density were determined using the Boltzmann plot method and Stark-broadened line profile analysis, respectively.