No abstract

No abstract

No abstract

The electron density and temperature of the laser induced silicon plasma were measured using two different methods. The plasma was produced via the interaction of high peak power Nd-YAG laser at the fundamental wavelength of 1064 nm with a plane solid iron target contain small traces of silicon as an element of minor concentration. The lines from the Si I at 288.15 nm and Si II-ionic lines at 413.08 and 634.71 nm were utilized to evaluate the plasma parameters. The reference plasma parameters were measured utilizing the Hα-line at 656.27 nm appeared in the spectra under the same condition. The electron density was measured utilizing the Stark broadening of the silicon lines and the temperature from the standard Saha-Boltzmann plot method. The comparison between electron densities from different silicon lines to that from the Hα-line reveals that the Si I-line at 288.15 nm contain some optical thickness while the Si II-ionic lines were found to be free from this effect. The measurements were repeated at different delay times between the laser and the camera in the range from 1 - 5 μsec. The electron density was found decreases from 2 × 10¹⁸ down to 4 × 10¹⁷ cm^–3. After correcting the spectral intensity at the Si I-line at 288.15 nm, the temperatures evaluated from the different methods were found in an excellent agreement and decreases from 1.25 down to 0.95 eV with delay time

No abstract

No abstract

In this article, we will report an experimental evidence of enhanced LIBS emission upon replacing a Bulk-Based ZnO target by the corresponding Nano-Based target. The plasma was initiated via interaction of a Nd:YAG laser at the fundamental wavelength with both targets in open air under the same experimental conditions. The measurements show an enhanced emission from the Zn I-lines at the wavelengths of 328.26, 330.29, 334.55, 468.06, 472.2, 481.01, 636.38 nm. The measurements were repeated at different delay times in the range from 1 to 5 μs at constant irradiation level and fixed gate time of 1 μs. The average enhancement over the different Zn I-lines was found increases exponentially up to 8-fold with delay time. The electron density to each plasma was measured utilizing the H_α-line appeared in the emitted spectra from each plasma and was found to give similar values. The electron temperatures were measured via Boltzmann plot method utilizing the relative intensities of the Zn I-lines and were found to give very close values. Moreover, the relative population density of the ground state of the zinc atoms (relative concentration) was measured spectroscopically utilizing the Boltzmann plot method and was found to increase in a very similar trend to that of enhancement. The results of the spectroscopic analysis conclude that these signal enhancements can be attributed to the higher concentration of neutral atoms in the Nano-Based material plasma with respect to the corresponding Bulk-based ZnO material

Spectral measurements of the H(α) Balmer series line and the continuum radiation are applied to draw inferences of electron density, temperature, and the level of self-absorption in laser ablation of a solid ice target in ambient air. Electron densities of 17 to 3.2×10(24) m(-3) are determined from absolute calibrated emission coefficients for time delays of 100-650 ns after generation of laser plasma using Q-switched Nd:YAG radiation. The corresponding temperatures of 4.5-0.95 eV were evaluated from the absolute spectral radiance of the continuum at the longer wavelengths. The redshifted, Stark-broadened hydrogen alpha line emerges from the continuum radiation after a time delay of 300 ns. The electron densities inferred from power law formulas agree with the values obtained from the plasma emission coefficients.