The polarization characteristics of single shot nanosecond laser-induced breakdown spectroscopy of Al

Abstract

The polarization-resolved laser-induced breakdown spectroscopy (PRLIBS) technique, which can significantly reduce the polarized emission from laser plasma by placing a polarizer in front of the detector, is a powerful tool to improve the line-to-continuum ratio in LIBS applications. It is shown that the continuum emission from the plasma produced through ablating an Al sample by nanosecond laser pulses is much more polarized than the discrete line emission with the single-pulse PRLIBS technique. The effects of laser fluence and detection angle on the Al polarization spectrum are systematically explored experimentally. The calculated result of the polarization spectrum as a function of laser fluence shows that it is in agreement with the experimental observations.

Time resolved anisotropic emission from an aluminium laser produced plasma

“…It is now perhaps useful to consider whether the rate of P ff is higher or lower than the rate of P fb . Equation (2) shows that if the electron temperature T e is lower than the ionization energy of the bound state to which the electron is captured (E I ), then the radiative recombination will be preferred. Under these experimental conditions, temperature analysis is not possible by optical spectroscopy, however, it can be inferred that just after ablation, radiative recombination is the main energy dissipation channel in the plasma.…”

“…The polarisation state of the light emitted from a laser produced plasma has recently become an area of interest in the wider laser plasma community. The reason for this is the observation that the continuum emission from a laser plasma tends to be more polarised than the line emission [1][2][3] which is useful for analytical techniques such as Laser Induced Breakdown Spectroscopy (LIBS). In previous studies, the degree of polarisation (P) of the light emitted from a laser produced plasma was measured for various focal positions, 1,4 laser energies, 4,5 background pressures, 5,6 incident laser polarisations, 3,4 detection directions, 4,6 and pulse durations.…”

“…This apparent null result compared with previous studies was resolved by taking the laser fluence into account. 2,6 In fact, this technique has birthed a subset of LIBS termed Polarisation-Resolved LIBS (PRLIBS).…”

Effects of pulse energy ratios on plasma characteristics of dual-pulse fiber-optic laser-induced breakdown spectroscopy

“…LIBS has become a promising chemical analytical technique due to its numerous advantages, such as no sample pre-treatment, minimal target damage, and rapid online measurement. [2,5] However, the traditional LIBS system (with direct-focusing laser) is limited to laboratories and professional analysts, because of its complicated optical structure, weak plasma radiation and unsatisfactory sensitivity for trace elements, which makes it impractical for complex industrial fields or hazardous extreme environments. [7] In order to improve the field applicability of LIBS, the fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) was proposed, in which the pulsed laser and plasma emission are transmitted via a long optical fiber, avoiding the large-scale optical arrangement on site and facilitating the determination of terminal spectral measurement parameters.…”

Influence of polarization of laser beam on emission intensity of femtosecond laser-induced breakdown spectroscopy*

“…Laser-induced breakdown spectroscopy (LIBS) is an effective technique to analyze the component of material without any preparation of sample. [1][2][3][4][5] The principle of this method is as follows. A high-energy laser beam is focused onto the target surface to produce plasma, and then plasma creates the emission spectrum: this emission spectrum is used to analyze the element composition.…”