Effect of Laser Energy and Atmosphere on the Emission Characteristics of Laser-Induced Plasmas

Abstract

The effects of laser energy and atmosphere on the emission characteristics of laser-induced plasmas were studied with the use of a Q-switched Nd: YAG laser over a laser energy range of 20 to 95 mJ. Argon, helium, and air were used as surrounding atmospheres, and the pressures were changed from atmospheric pressure to 1 Torr. The experimental results showed that the maximum spectral intensity was obtained in argon at around 200 Torr at a high laser energy of 95 mJ, whereas the line-to-background ratio was maximized in helium at around 40 Torr at a low energy of 20 mJ. The results are discussed briefly on the basis of the temporal and spatial observations of the laser-induced plasmas.

LIBS—An efficient approach for the determination of Cr in industrial wastewater

“…3 that LIBS signal increases monotonically with laser energy until the plasma density becomes too high for laser energy of 120 mJ. At still higher laser energy, the dense plasma formed by leading laser pulse starts absorbing energy from the later part of the laser pulse which leads to higher continuum emission [13,6] and lowers the analyte signal. Therefore, at higher energy, the decrease in LIBS signal may be due to shielding of laser light reaching to ablation surface.…”

Quantitative Analysis of Trace Lead in Tin-base Lead-free Solder by Laser-Induced Plasma Spectroscopy in Air at Atmospheric Pressure

“…7,8 In order to find the optimum laser energy giving a high spectral line intensity, the emission intensity of the Pb I 405.78-nm line was measured by changing the laser pulse energy from 10 to 90 mJ. The result is shown in Fig.…”

“…We studied the emission characteristics of the laser-induced plasma to improve the analytical performance, and showed the optimum conditions for quantitative analysis for non-conducting as well as conducting materials. [5][6][7][8][9][10][11][12][13] In our recent works, 14,15 we analyzed trace heavy metals of Pb, Cd, Hg and Cr in plastics by LIPS in argon at reduced pressure using time-resolved spectroscopy, and showed that these metal elements can be determined with detection limits of several tens ppm, and that the LIPS technique can be used for screening plastics for regulated elements.…”

Evaluation of the Potential of Laser-Induced Breakdown Spectroscopy for Detection of Trace Element in Liquid

“…At high laser energy, the plasma absorbs more laser energy and increases the plasma temperature, which leads to higher continuum emission. 28 The decrease in intensity of atomic lines may be due to shielding of laser light reaching to ablation surface or to loss in content of plasma energy due to generation of instability. Self-absorption may also contribute to the decrease in line emission intensity.…”