In the present work, we have studied the spatial evolution of the nickel alloy plasma produced by the fundamental (1064 nm) and second (532 nm) harmonics of a Q-switched Nd: YAG laser by placing the target material in air at atmospheric pressure. The four Ni I lines at 335.10 nm, 394.61 nm, 481.19 nm and 515.57 nm are used for the determination of electron temperature (Te) using Boltzmann plot method. The electron temperature is calculated as a function of distance from the target surface for both modes of Nd: YAG laser. In case of fundamental (1064 nm) mode of laser, the temperature varies from 13700 - 10270 K as the distance is varied from 0 to 2 mm. Whereas, in the case of second (532 nm) mode of laser it varies from 13270 - 9660 K for the same distance variation. The electron temperature has also been determined by varying the energy of the laser from 90 to 116 mJ, for the fundamental (1064 nm) harmonic and from 58 to 79 mJ for the second (532 nm) harmonics of the laser. The temperature increases from 14192 to 15765 K in the first case and from 13170 to 14800 K for the second case. We have also studied the spatial behavior of the electron number density in the plasma plume. The electron number density (Ne) in the case of fundamental (1064 nm) harmonic of the laser having pulse energy 125 mJ varies from 2.81 × 1016 to 9.81 × 1015 cm-3 at distances of 0 mm to 2.0 mm, whereas, in the case of second (532 nm) harmonic, with pulse energy 75 mJ it varies from 3.67 × 1016 to 1.48 × 1016 cm-3 for the same distance variation by taking Ni I line at 227.20 nm in both the cases.
F. S. Ferrero, J. Manrique, M. Zwegers and J. Campost, “Determination of Transition Probabilities of 3d84p-3d84s Lines of Ni II by Emission of Laser-Produced Plasmas,” Journal of Physics B: Atomic Molecular Physics, Vol. 30, No. 4, 1997, pp. 893-903.
A. Varga, R. M. G. Martinez, G. Zaray and F. Fodor, “Investigation of Effects of Cadmium, Lead, Nickel and Vanadium Contamination on the Uptake and Transport Processes in Cucumber Plants by TXRF Spectrometry,” Spectrochemica Acta Part B, Vol. 54, No. 10, 1999, pp. 1455- 1462. doi:10.1016/S0584-8547(99)00105-6
C. Aragon, J. Bengoechea and J. A. Aguilera, “Influence of the Optical Depth on Spectral Line Emission from Laser-Induced Plasmas,” Spectrochemica Acta Part B, Vol. 56, No. 2, 2001, pp. 619-628.
K. Wagatsuma and H. Honda, “Influence of the Optical Depth on Spectral Line Emission from Laser-Induced Plasmas,” Spectrochemica Acta Part B, Vol. 60, No. 12, 2005, pp. 1538-1544. doi:10.1016/j.sab.2005.10.004
C. Aragon, F. Penalba and J. A. Aguilera, “Spatial Distributions of the Number Densities of Neutral Atoms and Ions for the Different Elements in a Laser Induced Plasma Generated with a Ni-Fe-Al Alloy,” Analytical and Bio- analytical Chemistry, Vol. 385, No. 2, 2006, pp. 295-302.
S. Nakamura and K. Wagatsuma, “Emission Characteristics of Nickel Ionic Lines Excited by Reduced-Pressure Laser-Induced Plasmas Using Argon, Krypton, Nitrogen, and Air as the Plasma Gas,” Spectrochemica Acta Part B, Vol. 62, No. 9, 2007, pp. 1303-1310.
R. Mayo, M. Ortz and M. Plaza, “Measured Stark Widths of Several Ni II Spectral Lines,” Journal of Physics B: Atomic Molecular and Optical Physics, Vol. 41, No. 9, 2008, pp. 1-5. doi:10.1088/0953-4075/41/9/095702
M. Salik, M. Hanif and M. A. Baig, “Plasma Diagnostic Study of Alumina (Al2O3) Generated by the Fundamental and Second Harmonics of a Nd:YAG Laser,” IEEE Transactions on Plasma Science, Vol. 36, No. 9, 2011, pp. 1861-1866. doi:10.1109/TPS.2011.2159852
M. Hanif, M. Salik and M. A. Baig, “Quantitative Studies of Copper Plasma Using Laser Induced Breakdown Spectroscopy,” Journal of Optics and Lasers in Engineering, Vol. 49, No. 12, 2011, pp. 1456-1461.
D. Lacroix and G. Jeandel and C. Boudot, “Pectroscopic Characterization of Laser-Induced Plasma Created during Welding with a Pulsed Nd:YAG Laser,” Journal of Applied Physics, Vol. 81, 1997, pp. 6599-6606.
O. Barthélemy, J. Margot, S. Laville, F. Vidal, M. Chaker, T. W. Johnston, B. Le Drogoff and M. Sabsabi, “Investigation of the State of Local Thermodynamic Equilibrium of a Laser-Produced Aluminum Plasma,” Applied Spectroscopy, Vol. 59, No. 4, 2005, pp. 529-536.