Plasma properties of laser-ablated strontium target (original) (raw)
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Temperature and density spectroscopic measurements in different laser-generated plasmas
The European Physical Journal D, 2009
A pulsed Nd:Yag laser, at intensities of the order of 10 10 W/cm 2 , is employed to irradiate different thick metallic targets (Ti, Fe, Ag, and Ni) placed in vacuum. The obtained non-equilibrium plasmas are investigated with various analytical techniques. An electrostatic ion energy analyzer and different ion collectors are employed to monitor in situ the ions ejected from the plasma and to determine the core plasma temperature, the ion energy distributions and the ion angular emission. An optical spectrometer is employed to analyze the plasma corona emitted light vs. wavelength and to identify the emitted characteristic lines. The optical spectroscopy permitted to evaluate the electron temperatures and densities. Results show strong temperature and density gradients occurring in the laser-generated plasma plume.
OPTICAL SPECTROSCOPY IN LASER-GENERATED PLASMA AT A PULSE INTENSITY OF 1010 W/cm2
2008
A Nd:YAG laser operating at 1064 nm wavelength, 9 ns pulse width, 500 mJ maximum pulse energy is employed to irradiate different metallic targets (Al, Ti, Fe, Ag) in vacuum. Optical spectroscopy and ion energy analysis are employed to characterize the laser-plasma. The plasma temperatures and densities are measured through optical spectroscopy, ion energy distributions and fast CCD imaging. Results indicated that high temperature and density gradients occur. The temperature in the core zone is in the order of 100 eV while in the coronal zone it in the order of 1 eV. The maximum plasma density is in the order of 5·1016 cm-3 in the coronal zone.
A study of the laser plasma parameters at different laser wavelengths
Spectrochimica Acta Part B: Atomic Spectroscopy, 2002
Diagnostic of laser produced aluminum plasma was performed adopting a spectroscopic technique. A Q-switched Nd:YAG laser at wavelengths 1064, 532 and 355 nm with maximum energies of 500, 100 and 60 mJ, respectively, and pulse duration of 7 ns with repetition rate of 1 Hz was used. The measurements were carried out to determine the spatial electron temperature using the Boltzmann plot for the Al II lines and the spatial profile of the electron density using Stark broadening formula for the three different laser wavelengths. The maximum attainable value of the electron temperature was found at a certain distance away from the target surface depending on the laser wavelength. The electron density reaches its highest value near the target surface. The measurements are then compared with available published experiment and theory and are found to be in agreement with the theory of local thermodynamic equilibrium (LTE). ᮊ
Iraqi Journal of Science, 2019
In this paper, Al and Cu Plasmas that produced by pulsed Nd:YAG laser with fundamental wave length with a pulse duration of 6 nS focused onto Al and Cu targets in atmospheric air are investigated spectroscopically. The influence of pulse laser energy on the some Al and Cu plasmas characteristics was diagnosed by using optical emission spectroscopy for the wavelength range 320-740 nm. The results observed that the increase of pulse laser energy causes to increase all plasma characteristics of both plasmas under study and shown increasing of the emission line intensity. The appearance of the atomic and ionic emission lines of an element in the emission spectrum depends on the ionization energy of target atoms. The plasma characteristics are subjected to the ionization energy of the target element and laser energy.
Investigations on low temperature laser-generated plasmas
Laser and Particle Beams, 2008
A nanosecond pulsed Nd-Yag laser, operating at an intensity of about 10 9 W/cm 2 , was employed to irradiate different metallic solid targets (Al, Cu, Ta, W, and Au) in vacuum. The measured ablation yield increases with the direct current (dc) electrical conductivity of the irradiated target. The produced plasma was characterized in terms of thermal and Coulomb interaction evaluating the ion temperature and the ion acceleration voltage developed in the non-equilibrium plasma core. The particles emission produced along the normal to the target surface was investigated measuring the neutral and the ion energy distributions and fitting the experimental data with the "Coulomb-Boltzmann-shifted" function. Results indicate that the mean energy of the distributions and the equivalent ion acceleration voltage of the non-equilibrium plasma increase with the free electron density of the irradiated element.
Comparison of zinc and cadmium plasma parameters produced by laser-ablation
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007
We report the measurement of the zinc and cadmium plasma parameters produced by the fundamental, second, and third harmonics of the neodymium-doped yttrium aluminium garnet laser. The excitation temperature has been determined from the Boltzmann plot method, whereas the electron number density is estimated from the Stark broadened profile of several spectral lines. The temporal evolution of the plasma has also been investigated. Besides, we present experimental relative transition probabilities of the Zn (4s5s 3 S 1 → 4s4p 3 P 0,1,2) and Cd (5s6s 3 S 1 → 5s5p 3 P 0,1,2) triplets and compare our data with that listed in the National Institute of Standards and Technology database. The experiments have been performed in air but also in He, Ne and Ar atmosphere to study the effects of ambient gas environment on the emission intensity of the atomic and ionic lines and on the plasma parameters.
Spectroscopic evolution of plasma produced by Nd-YAG laser
2014
The aim of this paper is to evaluate the effect of the laser beam energy on the properties of the plasma generated by focusing an intense laser beam on Zn solid targets in air at atmospheric pressure. Plasma is generated using Nd-YAG pulsed laser from Quanta at the fundamental and visible wavelength, its duration being 6 ns. This paper has been done at laser energies of 350, 200, and 100 mJ for the fundamental wavelength, and of 400, 200, and 100 mJ for the second-harmonic laser. The emitted light is collected by a fiber cable and illuminates the entrance slit of an Acton grating spectrometer equipped with intensified charge coupled device camera from photoionization at several delay time intervals. Boltzmann plots of Fe I spectral lines are used to obtain the excitation temperature evolution of the produced plasmas. The evolution of the plasma density is obtained from the Stark full-width at half-maximum of the Si I line at 288.16 nm and Al II line at 281.6 nm. In this paper, we are able to perform experiments at different laser energies and different delay times, which also allow us to study the dependence of the plasma evolution on the laser wavelength.
Effect of laser energy and atmosphere on the emission characteristics of laser-induced plasmas
Applied Spectroscopy, 1993
The effects of laser energy and atmosphere on the emission characteristics of laser-induced plasmas were studied with the use of a Q-switched Nd:YAG laser over a laser energy range of 20 to 95 mJ. Argon, helium, and air were used as surrounding atmospheres, and the pressures were changed from atmospheric pressure to 1 Torr. The experimental results showed that the maximum spectral intensity was obtained in argon at around 200 Torr at a high laser energy of 95 m J, whereas the line-tobackground ratio was maximized in helium at around 40 Torr at a low energy of 20 mJ. The results are discussed briefly on the basis of the temporal and spatial observations of the laser-induced plasmas.
Laser-induced plasma as a function of the laser parameters and the ambient gas
2014
Laser-induced breakdown spectroscopy (LIBS) has been invented for more than 50 years, which analyzes the spectrum of the laser-induced plasma to determine the elemental composition of the ablated sample. Recently, LIBS technique has been well developed and applied in different domains, for example oceanic exploration, pollution monitoring in the environment. LIBS uses the ablation plasma as a light source that contains the elemental composition information of the sample. However, the laser-induced plasma exhibits a transient behavior. Although time-resolved and gated detection can greatly improve the performance of the LIBS technique especially that of calibration-free LIBS (CF-LIBS) with a better determination of plasma temperature, the temporal evolution of the plasma is correlated to its morphology and its spatial inhomogeneity. The determination of the morphology as well as the internal structure of the plasma together with their evolution during plasma expansion into the ambien...