Sony, George; Dr.V P N Nampoori(Cochin University of Science & Technology, September , 2011)
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Abstract:
The present thesis report the results obtained from the studies carried out on the
laser blow off plasma (LBO) from LiF-C (Lithium Fluoride with Carbon) thin film
target, which is of particular importance in Tokamak plasma diagnostics. Keeping
in view of its significance, plasma generated by the irradiation of thin film target by
nanosecond laser pulses from an Nd:YAG laser over the thin film target has been
characterized by fast photography using intensified CCD. In comparison to other
diagnostic techniques, imaging studies provide better understanding of plasma
geometry (size, shape, divergence etc) and structural formations inside the plume
during different stages of expansion.
Description:
International School of Photonics,Cochin University of Science and Technology
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
Tintu, R; Dr. Sheenu, Thomas(Cochin University of Science and Technology, June , 2011)
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Abstract:
In this context,in search of new materials based on chalcogenide glasses,we have developed a novel technique for fabrication of chalcogenide nano composites which are presented in this theis.The techniques includes the dissolution of bulk chalcogenide glasses in amine solvent.This solution casting method allows to retain the attractive optical properties of chalcogenide glasses enabling new fabrication routes for realization of large area thick-thin films with less cost. Chalcogenide glass fiber geometry opens new possibilities for a large number of applications in optics,like remote temperature measurements ,CO2 laser power delivery, and optical sensing and single mode propagation of IR light.We have fabricated new optical polymer fibers doped with chalcogenide glasses which can be used for many optical applications.The present thesis also describes the structural,thermal and optical characterization of certain chalocogenide based materials prepared for different methods and its applications.
Description:
International School of Photonics, Cochin University of Science and Technology
Ritty J, Nedumpara; Dr. Radhakrishnan, P(Cochin University of Science and Technology, February , 2007)
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Abstract:
Observing the wide possibilities of fluorescent dyes, an exhaustive investigation is
done in laser dyes mainly focusing on Coumarin 540 which has a very strong
emission in the green region. The photophysics of the dye is studied in detail in a good
number of solvent environments. The results of the amplified spontaneous emission
and lasing behaviour in both dye solution and different polymer solid state matrices
and the ptotostability of the these matrices are investigated using the photoacoustic technique and the same are also included in this thesis. The energy transfer behaviour
in dye mixtures which could be utilized for laser studies and bio-analysis are also
presented. The nonlinear characterization of Coumarin540 forms the last part of the
experimental investigations presented in the thesis.
Description:
International School of Photonics,
Cochin University of Science and Technology
Pradeep Chandran, C; V P N Nampoori; Radhakrishnan, P(Cochin University of Science and Technology, January 10, 2016)
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Abstract:
We live in an Information age, which is marked by the onset of digital
revolution during or after the latter half of the 20th century. In this era, we saw
sweeping changes in digital computing and communication technology. We largely
depend on electronics and photonics for hardware requirements to aid this
technology. With the assistance of modern technology, electronic devices have
become an indispensable tool in our everyday life.
Inorganic semiconductor materials like silicon and gallium arsenide have been
exploited for the on-growing demands of digital revolution. Fifty years of continuous
research and technological advancements have pushed these materials to their
theoretical efficiency limit. On the other hand, the rapid advancement in technology
has created a huge electronic waste which pose a threat to the environment. The
scarcity of inorganic materials such as gallium and indium is an alarming factor and it
is estimated that these will run out completely in the next 20 years. The availability of
new suitable materials is crucial for the development of semiconductor technology.
With much promise of delivering low-cost and energy efficient materials, organic
semiconductors such as conjugated polymers and small molecules have opened up
new avenues for research. Despite the intense effort by scientists and researchers, the
performance and stability of organic devices have taken a back seat. Therefore an
immediate large-scale replacement of inorganic components by organic counterparts
are not foreseen in the near future. Although research is underway to improve the
performance of organic materials, it is important to constantly search for new
materials.Nature is a big treasure-trove of successfully conducted experiments by
natural selection. Inspired by its apparent simplicity and actual complexity,
researchers look out for natural materials or synthetic materials mimicked from
natural models, systems or elements. Bio-inspired photonics use natural design as
their inspiration to solve human problems and channel these solutions in new
directions. It is promising that natural and nature-inspired materials can achieve the
ambitious goal of ‘green’ technology for sustainable future.