Babar Rashid - Academia.edu (original) (raw)

Papers by Babar Rashid

International Journal of Modern Physics B, 2007

We report measurements of the copper plasma parameters generated by the fundamental, second and t... more We report measurements of the copper plasma parameters generated by the fundamental, second and third harmonics of a Nd:YAG laser. The 3d 9 4s5s 2 D 3/2 → 3d 9 4s4p 2 F 5/2 at 464.25 nm, 4p 2 P 3/2 → 3d 9 4s 2 D 5/2 at 510.55 nm, 4d 2 D 3/2 → 4p 2 P 1/2 at 515.32 nm 4d 2 D 5/2 → 4p 2 P 3/2 at 521.82 nm and 4p 2 P 3/2 → 3d 9 4s 2 D 3/2 at 570.02 nm transitions have been used to estimate the electron temperature through the Boltzmann plot method. The number density has been estimated from the Stark broadened profiles of the spectral lines. The spatial behaviour of the electron temperature and number density has been examined at different ambient air pressures and with laser irradiance. The temperature and number density are found to be in the range from 14700 to 13600 K and 2.

Physics of Plasmas, 2011

We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma... more We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma generated by the 1064 nm Nd: YAG laser. The spectrum reveals Rydberg transitions; nd 2 D 3=2,5=2 ! 3p 2 P 1=2,3=2 (n ¼ 3 -8), ns 2 S 1=2 ! 3p 2 P 1=2,3=2 (n ¼ 4-6), and the dominant spectral lines of the other constituent elements. We have extracted the relative abundance of the impurities using the relative intensity ratio method. Besides, we have calculated the electron temperature ($7580 K) from the Boltzmann plot method and the electron number densities ($1.4 Â 10 17 =cm 3 ) from the Stark widths of the aluminum spectral lines. The plasma parameters determined in the present work are in agreement with that reported in the literature. The molecular vibrational transitions of the AlO free radical associated with the B 2 P !X 2 P band system have also been identified.

Journal of Physics D: Applied Physics, 2006

We report the first measurements of the optical emission spectra of mercury plasma produced by th... more We report the first measurements of the optical emission spectra of mercury plasma produced by the fundamental, second and third harmonics of a Nd : YAG laser, which reveals numerous transitions due to the neutral and singly ionized mercury. The excitation temperature has been determined from the Boltzmann plots, whereas the electron number density is estimated from the Stark broaden profile of the spectral lines. The estimated range of the excitation temperature and the electron number density is (7000-14000) K and (3.6 × 10 16 to 2.5 × 10 17 ) cm −3 , respectively. The behaviour of the excitation temperature and the electron number density with the laser irradiance has been studied. The spatial distribution of the temperature and the electron number density has also been investigated besides the studies of absorption in the plasma through inverse bremstrahlung and photoionization.

Journal of Applied Physics, 2006

Optical measurements of the cadmium plasma produced by the fundamental, second, and third harmoni... more Optical measurements of the cadmium plasma produced by the fundamental, second, and third harmonics of a Nd:YAG laser are reported. The excitation temperature and ionic temperature have been determined from the Boltzmann plot and Saha equation, whereas the number density is estimated from the Stark broadened profile of the spectral lines. The variations in the excitation temperature and number density with the ambient air pressure as well as with the laser irradiance have been studied. Besides, the spatial distributions of the temperature and number density have been investigated.

Journal of Applied Physics, 2008

Optical emission spectroscopy is used to characterize the laser-produced strontium plasma by usin... more Optical emission spectroscopy is used to characterize the laser-produced strontium plasma by using the fundamental, second, and third harmonics of a Nd:YAG laser. Variations in the electron temperature ͑T e ͒ and number density ͑N e ͒ as a function of distance, laser irradiance, and ambient gas pressure have been studied by using the emission lines of neutral strontium. In addition, absorption mechanisms responsible for the variation of the electron temperature and number density and the dependence of the spectral line intensities on the ambient gas pressure and laser irradiance are discussed.

The European Physical Journal D, 2007

In the present work, we have studied the spatial evolution of the aluminum plasma produced by the... more In the present work, we have studied the spatial evolution of the aluminum plasma produced by the fundamental (1064 nm), second (532 nm) and third (355 nm) harmonics of a Q-switched pulsed Nd:YAG laser. The experimentally observed line profiles of neutral aluminum have been used to extract the excitation temperature using Boltzmann plot method whereas the electron number density has been determined from the Stark broadened profiles. Besides we have studied the variation of excitation temperature and electron number density as a function of laser irradiance at atmospheric pressure. In addition, we have performed quantitative analysis of photon absorption and vapor ionization mechanism at three laser wavelengths and estimated the inverse bremsstrahlung (IB) absorption and photoionization (PI) coefficients. The validity of the assumption of local thermodynamic equilibrium is discussed in the light of the experimental results.

Asian journal of Chemistry, 2013

In present study, the Nd:YAG laser generated copper plasma has been evaluated as a function of di... more In present study, the Nd:YAG laser generated copper plasma has been evaluated as a function of distance (0.5-5 mm) at 17.6 and 88.6 mJ. The excitation temperature was determined using Boltzmann plot method of the transitions (4p P3/2 → 3d 4s 2 D5/2) at 510.34 nm (4d 2 D3/ 2 → 4p 2 P1/2) at 515.12 nm, (4d 2 D5/2 → 4p 2 P3/2) at 521.64, whereas electron number density was measured by Stark Broadening method. The spatial behaviour of the electron temperature and electron number density was measured at ambient air pressures. The electron temperature was found in the ranges from 16790-9090 K, while electron number density was 1.53 × 10 17 -1.85 × 10 17 and 1.35 × 10 17 -1.87 × 10 17 cm -3 , respectively for 17.6 and 88.6 mJ energy. The relationship of electron number density and electron temperature found directly related to laser irradiation, while they were inverse to the distance form the target surface.

Physics of Plasmas, 2011

PHYSICS OF PLASMAS 18, 073301 (2011) Downloaded 25 Aug 2011 to 140.78.102.91. Redistribution subj... more PHYSICS OF PLASMAS 18, 073301 (2011) Downloaded 25 Aug 2011 to 140.78.102.91. Redistribution subject to AIP license or copyright; see http://pop.aip.org/about/rights_and_permissions

International Journal of Modern Physics B, 2007

We report measurements of the copper plasma parameters generated by the fundamental, second and t... more We report measurements of the copper plasma parameters generated by the fundamental, second and third harmonics of a Nd:YAG laser. The 3d 9 4s5s 2 D 3/2 → 3d 9 4s4p 2 F 5/2 at 464.25 nm, 4p 2 P 3/2 → 3d 9 4s 2 D 5/2 at 510.55 nm, 4d 2 D 3/2 → 4p 2 P 1/2 at 515.32 nm 4d 2 D 5/2 → 4p 2 P 3/2 at 521.82 nm and 4p 2 P 3/2 → 3d 9 4s 2 D 3/2 at 570.02 nm transitions have been used to estimate the electron temperature through the Boltzmann plot method. The number density has been estimated from the Stark broadened profiles of the spectral lines. The spatial behaviour of the electron temperature and number density has been examined at different ambient air pressures and with laser irradiance. The temperature and number density are found to be in the range from 14700 to 13600 K and 2.

Physics of Plasmas, 2011

We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma... more We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma generated by the 1064 nm Nd: YAG laser. The spectrum reveals Rydberg transitions; nd 2 D 3=2,5=2 ! 3p 2 P 1=2,3=2 (n ¼ 3 -8), ns 2 S 1=2 ! 3p 2 P 1=2,3=2 (n ¼ 4-6), and the dominant spectral lines of the other constituent elements. We have extracted the relative abundance of the impurities using the relative intensity ratio method. Besides, we have calculated the electron temperature ($7580 K) from the Boltzmann plot method and the electron number densities ($1.4 Â 10 17 =cm 3 ) from the Stark widths of the aluminum spectral lines. The plasma parameters determined in the present work are in agreement with that reported in the literature. The molecular vibrational transitions of the AlO free radical associated with the B 2 P !X 2 P band system have also been identified.

Journal of Physics D: Applied Physics, 2006

We report the first measurements of the optical emission spectra of mercury plasma produced by th... more We report the first measurements of the optical emission spectra of mercury plasma produced by the fundamental, second and third harmonics of a Nd : YAG laser, which reveals numerous transitions due to the neutral and singly ionized mercury. The excitation temperature has been determined from the Boltzmann plots, whereas the electron number density is estimated from the Stark broaden profile of the spectral lines. The estimated range of the excitation temperature and the electron number density is (7000-14000) K and (3.6 × 10 16 to 2.5 × 10 17 ) cm −3 , respectively. The behaviour of the excitation temperature and the electron number density with the laser irradiance has been studied. The spatial distribution of the temperature and the electron number density has also been investigated besides the studies of absorption in the plasma through inverse bremstrahlung and photoionization.

Journal of Applied Physics, 2006

Optical measurements of the cadmium plasma produced by the fundamental, second, and third harmoni... more Optical measurements of the cadmium plasma produced by the fundamental, second, and third harmonics of a Nd:YAG laser are reported. The excitation temperature and ionic temperature have been determined from the Boltzmann plot and Saha equation, whereas the number density is estimated from the Stark broadened profile of the spectral lines. The variations in the excitation temperature and number density with the ambient air pressure as well as with the laser irradiance have been studied. Besides, the spatial distributions of the temperature and number density have been investigated.

Journal of Applied Physics, 2008

Optical emission spectroscopy is used to characterize the laser-produced strontium plasma by usin... more Optical emission spectroscopy is used to characterize the laser-produced strontium plasma by using the fundamental, second, and third harmonics of a Nd:YAG laser. Variations in the electron temperature ͑T e ͒ and number density ͑N e ͒ as a function of distance, laser irradiance, and ambient gas pressure have been studied by using the emission lines of neutral strontium. In addition, absorption mechanisms responsible for the variation of the electron temperature and number density and the dependence of the spectral line intensities on the ambient gas pressure and laser irradiance are discussed.

The European Physical Journal D, 2007

In the present work, we have studied the spatial evolution of the aluminum plasma produced by the... more In the present work, we have studied the spatial evolution of the aluminum plasma produced by the fundamental (1064 nm), second (532 nm) and third (355 nm) harmonics of a Q-switched pulsed Nd:YAG laser. The experimentally observed line profiles of neutral aluminum have been used to extract the excitation temperature using Boltzmann plot method whereas the electron number density has been determined from the Stark broadened profiles. Besides we have studied the variation of excitation temperature and electron number density as a function of laser irradiance at atmospheric pressure. In addition, we have performed quantitative analysis of photon absorption and vapor ionization mechanism at three laser wavelengths and estimated the inverse bremsstrahlung (IB) absorption and photoionization (PI) coefficients. The validity of the assumption of local thermodynamic equilibrium is discussed in the light of the experimental results.

Asian journal of Chemistry, 2013

In present study, the Nd:YAG laser generated copper plasma has been evaluated as a function of di... more In present study, the Nd:YAG laser generated copper plasma has been evaluated as a function of distance (0.5-5 mm) at 17.6 and 88.6 mJ. The excitation temperature was determined using Boltzmann plot method of the transitions (4p P3/2 → 3d 4s 2 D5/2) at 510.34 nm (4d 2 D3/ 2 → 4p 2 P1/2) at 515.12 nm, (4d 2 D5/2 → 4p 2 P3/2) at 521.64, whereas electron number density was measured by Stark Broadening method. The spatial behaviour of the electron temperature and electron number density was measured at ambient air pressures. The electron temperature was found in the ranges from 16790-9090 K, while electron number density was 1.53 × 10 17 -1.85 × 10 17 and 1.35 × 10 17 -1.87 × 10 17 cm -3 , respectively for 17.6 and 88.6 mJ energy. The relationship of electron number density and electron temperature found directly related to laser irradiation, while they were inverse to the distance form the target surface.

Physics of Plasmas, 2011

PHYSICS OF PLASMAS 18, 073301 (2011) Downloaded 25 Aug 2011 to 140.78.102.91. Redistribution subj... more PHYSICS OF PLASMAS 18, 073301 (2011) Downloaded 25 Aug 2011 to 140.78.102.91. Redistribution subject to AIP license or copyright; see http://pop.aip.org/about/rights_and_permissions