Optical depth measurement of self-reversed line emitted from in-homogenous plasma in laser induced breakdown spectroscopy

Abstract

In this work, an original method is proposed and used for measurement of the optical depth of a self-reversed spectral line. A theoretical approach is utilized in an inhomogenous laser induced plasma at local thermodynamic to simulate self-reversed line and then to get the main line profile without self-absorption. The spatial and temporal evolution of optical depth of two spectral lines of Ca II at 393.4 nm and 396.9 nm is studied. Furthermore, the variation of optical depth versus the concentration of species emitter inside of plasma plume is investigated. In addition, the validity of this method is affirmed during comparison with results obtained by other techniques.