Dann, V J; Dr.Nampoori,V P N; Dr.Nandakumaran,V M(Cochin University of Science & Technology, October , 2008)
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Abstract:
Laser induced plasma (LIP) emissions from some metal oxide targets were
studied with corresponding metal targets of pure quality as a reference. Atomic emissions
in the visible region were used in the spectroscopic procedures of LIP characterization.
The studies were meant to throw light into LIP dynamics and they provided many
experimental results which improved the general awareness of plasma state.When target materials were photo-ablated with an energetically suitable laser
pulse, they developed electric charges in them.An electrical signal which was delivered
from the target served as an alternative probe signal for the diagnostics of LIP and to
track different charged states in the plasma. The signal showed a double peak distribution
with positive polarity and a modified time of flight with various voltage levels of a given
polarity.The expansion dynamics of LIP in magnetic field were also investigated
by monitoring the voltage transients generated at the target.
Description:
International School of Photonics,
Cochin University of Science and Technology
Harilal, S S; Riju, C Issac; Bindhu, C V; Geetha K, Varier; Nampoori, V P N; Vallabhan, C P G(Pramana, February , 1996)
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Abstract:
Analysis of the emission bands of the CN molecules in the plasma generated from
a graphite target irradiated with 1-06/~m radiation pulses from a Q-switched Nd:YAG laser has
been done. Depending on the position of the sampled volume of the plasma plume, the intensity
distribution in the emission spectra is found to change drastically. The vibrational temperature
and population distribution in the different vibrational levels have been studied as function of
distance from the target for different time delays with respect to the incidence of the laser pulse.
The translational temperature calculated from time of flight is found to be higher than the
observed vibrational temperature for CN molecules and the reason for this is explained.
Padmaja, G; Ravi Kumar, A V; Vidyalal, V; Radhakrishnan, P; Nampoori, V P N; Vallabhan, C P G(Springer, May , 1989)
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Abstract:
Laser induced plasma emission spectra from highT c superconducting samples of YBa2Cu3O7 and GdBa2Cu3O7 obtained with 1.06µm radiation from a Q switched Nd:YAG laser beam has been analysed. The results clearly show the presence of diatomic oxides in addition to ionized species of the constituent metals in the plasma thus produced.