Optik 125 (2014) 2327–2331 Contents lists available at ScienceDirect Optik jo ur nal homepage: www.elsevier.de/ijleo Characterization of laser induced tantalum plasma by spatio-temporal resolved optical emission spectroscopy A. Alkhawwam ∗ , K. Alnama, A. Jazmati, M.D. Zidan Physics Department, Atomic Energy Commission, Damascus, Syria a r t i c l e i n f o Article history: Received 20 May 2013 Accepted 14 October 2013 Keywords: Laser induced plasma Tantalum Optical emission spectroscopy Spatio-temporal evolution Electron density a b s t r a c t The spatial and temporal behavior of the tantalum plasma produced in air by third harmonic Nd:YAG laser (0.6 GW cm -2 ) has been studied using optical emission spectroscopy. Excitation temperature and electron density have been estimated from the analysis of spectral data as well as their spatio-temporal evolutions. As the delay time increases from 400 to 2000 ns, the excitation temperature has found to decrease from 10,000 K to 7900 K. The value of N e decreases continuously from 4 × 10 18 near the zero position to 5 × 10 17 in a linear approach along with the propagation axe of the plasma plume. Laser-supported consumption wave regime has been proposed to explain the propagation of the plasma. © 2013 Elsevier GmbH. All rights reserved. 1. Introduction Laser Induced Plasma Spectroscopy (LIPS) is one of the analyti- cal and diagnostic techniques that has been really boosted recently [1,2], depending on its original concept based on induced spectral emission after exciting a small quantity of the material by high power laser pulses. The emitted radiations were recorded and ana- lyzed by optical emission spectroscopy (OES) system. In order to investigate and monitor the emission spectra with time resolution of nanoseconds, an advanced triggered and gated intensified CCD camera in the nanosecond regime is needed. The time resolved LIPS has become the most popular way to improve the performance of the laser induced plasma spectrometry [3,4]. Tantalum is a rare metal, widely used in electronic components such as superconducting transition edge temperature sensor [5], capacitors and resistances in oxide form used in manufacturing a hearing devices [6]. Tantalum layers are used as a robust coating of surfaces requiring a high resistance against wear, corrosion as well as immunity to chemical and biological attack such as surgical tools and implants [7–9]. A variety of techniques including sputtering [10,11], e-beam evaporation [12], plasma-enhanced atomic layer deposition [13] and laser ablation [14–16] have been used for tantalum and its compounds thin films deposition. In order to get a better control on the pulsed laser depo- sition processes, a spatio-temporal study by optical emission ∗ Corresponding author. Tel.: +963 11 2132580; fax: +963 11 6112289. E-mail address: pscientific@aec.org.sy (A. Alkhawwam). spectroscopy of Ta plasma in air, could be considered as a first step and it will be essential to characterize the plasma plume during the films deposition in further detailed study. The most important plasma parameters are excitation temperature and elec- tron density. These parameters depend highly on the experimental conditions such as laser wavelength, laser fluence, ambient gas pressure, target materials and the geometrical set up of the col- lection optics [1,2]. Torrisi et al. have studied the Ta plasma in vacuum by nanosec- ond laser at different wavelengths and fluencies, where they explore the emission of neutrals and ionic species of the Ta plasma [17,18]. They found that the electron temperature and density of the plasma are about 50 eV and 10 18 cm -3 respectively. In other work, Torrisi et al. have studied the spatio-temporal behavior of laser-generated pulsed plasmas at 1064 nm of Ta [19], by means of Langmuir probes, ion collectors, and ion energy analyzers. The electron density value in their work is similar to what it is obtained in our work. Novodvorsky et al. have studied the erosion plume of tantalum targets in vacuum formed by excimer laser (308 nm) [20]. They studied the electron temperature distribution over the plume using Langmuir probe and optical emission spectroscopy. Their results showed that the excitation temperature of the Ta plume is not uniform and it has a maximum value in front of the plume. This article presents, up to the best of our knowledge, the first spatial and temporal study of the tantalum plume produced in air. Intensity, excitation temperature, and electron density distribution as a function of space and time were investigated from a large num- ber of optical emission spectra taken at different points of the plume along the propagation axe with different delay times. 0030-4026/$ – see front matter © 2013 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.ijleo.2013.10.073