Emission Characteristics of Laser-Induced Plasma Using Collinear Long and Short Dual-Pulse Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract

Collinear long and short dual-pulse laser-induced breakdown spectroscopy (DP-LIBS) was employed to clarify the emission characteristics from laser-induced plasma. The plasma was sustained and became stable by the long pulse-width laser with the pulse width of 60 μs under free running (FR) conditions as an external energy source. Comparing the measurement results of stainless steel in air using single-pulse LIBS (SP-LIBS) and DP-LIBS, the emission intensity was markedly enhanced using DP-LIBS. The temperature of plasma induced by DP-LIBS was maintained at a higher temperature under different gate delay time and short pulse-width laser power conditions compared with those measured using short SP-LIBS. Moreover, the variation rates of plasma temperatures measured using DP-LIBS were also lower. The superior detection ability was verified by the measurement of aluminum sample in water. The spectra were clearly detected using DP-LIBS, whereas it cannot be identified using SP-LIBS of short and long pulse widths. The effects of gate delay time and short pulse-width laser power were also discussed. These results demonstrate the feasibility and enhanced detection ability of the proposed collinear long and short DP-LIBS method.

Improving the Detection Sensitivity for Laser-Induced Breakdown Spectroscopy: A Review

“…For example, they proposed the collinear long and short DP-LIBS to detect the solid sample. The results showed that the plasma became more stable and sustained when using a long pulse-width laser (pulse width of 60 µs) as external energy, and marked enhancement were obtained compared to single-pulse LIBS [50]. Further, the spectral signal was enhanced about 3-7 times by long-short DP-LIBS comparing to conventional SP-LIBS when detecting the standard steel samples [51].…”

Sample Temperature Effect on Steel Measurement Using SP-LIBS and Collinear Long-short DP-LIBS

“…Thus FR laser pulse has lower energy density which is not enough to produce an observable plasma emission. [25][26][27] A short pulse laser with wavelength of 1 064 nm, pulse width of 5-8 ns, pulse energy of 24.5 mJ and frequency of 10 Hz is generated by the Laser (LOTIS TII, LS-2134U). The reflected short pulse laser beam combined with the long pulse laser beam by polarization prism to realize the collinear long-short DP-LIBS.…”

“…It demonstrated the feasibility and enhanced detection ability of long-short DP-LIBS method due to pre-heating and re-heating effects of long pulse. [25][26][27] In this paper, the collinear long-short DP-LIBS was employed to discuss the sample temperature effect on steel measurement for the improvement of LIBS technique. The standard steel sample with different sample temperature was measured by single pulse LIBS (SP-LIBS) and collinear long-short DP-LIBS respectively to systematically study the sample temperature effects for steel measurement.…”

Signal Improvement for Underwater Measurement of Metal Samples Using Collinear Long-Short Double-Pulse Laser Induced Breakdown Spectroscopy

“…The long and short double-pulse LIBS method was proposed by our group and it has been named as LS-DP-LIBS [28,29]. In previous studies [30,31], LS-DP-LIBS has been compared with SP-LIBS based on the measurement results in an air atmosphere.…”