Laser-plasma interaction; Emission of electromagnetic radiation; Thermodynamics of plasma;INDUCED BREAKDOWN SPECTROSCOPY; CARBON; ARGON; LIBS; AIR

In this study, graphite laser induced plasma dynamics are investigated by optical emission spectroscopy. Graphite plasma is generated using a 1064 nm Nd: YAG laser in helium environment under different ambient pressures. Characteristics of graphite spectra as lines intensity variations and signal to noise ratio are presented with main focus on the influence of the helium environment and pressure on plasma dynamics. Carbon atomic emission lines are used to study the dynamical behavior of plasma such as the excitation temperature and electron density to describe emission differences in different ambient conditions. The excitation temperature and plasma electron density are the primary factor contribute to the differences among the atomic carbon emission in different ambient pressures.

INDUCED BREAKDOWN SPECTROSCOPY; LIBS; SAMPLES

In this study, Nd: YAG laser pulse is used to ablate the Magnesium sample for laser induced breakdown spectroscopy analysis. The emission lines are plotted for ionic and atomic element of Mg I and Mg II respectively. The emission lines of Mg I and Mg II were recorded at wavelength of 279.55 nm, 280.27 nm and 285.21 nm. The analysis including the different of gate delay, determination of signal to background ratio and calibration curve of different concentration of magnesium is discussed in details.