Established in 1933 by the Nobel Laureate C.V. Raman, the Department of Physics soon evolved into the leading centre in the country for advanced postgraduate education and cutting-edge research in physics. The largest number of Ph.D.s in physics in India -- 110 since 1998 -- come from this department. Graduates from the department have gone on to distinguished careers in science and occupy leading positions in research institutes in India and the world over. ...more
Novel Route to Achieve Hierarchical Ordering of Colloidal Crystals
Colours are one of the most striking ways in which Nature showcases her beauty. Be it the vividly-patterned wings of the butterfly,
the elegant
feathers of the peacock or the myriad-coloured birds--they all enthral, mesmerize and charm each of us alike--from a child to an
adult, a layman to a
scientist, a writer to a poet.
However, unlike the colours due to dyes and pigments, most of the colours observed in living organisms are primarily due to
underlying periodic
structures. Nature remarkably self-assembles these structures from individual building blocks that could be as small as a millionth
of a millimetre.
Apart from their aesthetic appeal, realization of these structural colours has tremendous applications in our everyday life.
Structural colours can
have a significant impact on modern electronic gadgets such as smartphones and laptops. The display panel of the devices based on
structural colours
will use the ambient light itself to power themselves, which in turn can also solve the problems of poor visibility of screens in
excess glare.
Over the last decades, scientists across the world are striving hard to realize structural colours in laboratory that can mimic the
beautiful colours
seen in nature. However, the major impediments in realizing them have been the low mobility of the building blocks, namely colloids
and nanoparticles,
on surfaces. Owing to their large size, these particles do not diffuse significant distances on the surfaces before meeting another
one of their kind,
so that they would grow further on. For any useful application, tuning of this separation between the growing centres is very
crucial.
In a major breakthrough, scientists at the city's Jawaharlal Nehru Centre for Advanced Scientific Research and Indian Institute of
Science have
developed a new strategy wherein they can precisely control the spacing between these growing centres. They have taken recourse to
soft-lithography to
engineer surfaces with inhomogeneous yet periodic structures. With great ingenuity, they have been able to introduce attraction
between the building
blocks and the engineered surfaces that locomote the building blocks to the desired sites before the ensuing growth could begin.
This technique gives
a facile control over the growing structures and that too with much-needed simplicity in the growth techniques. These findings that
will shortly
appear in prestigious scientific journal "Proceedings of National Academy of Sciences, U.S.A. (2016)รข" aree expected to have a crucial
impact on the
photonics industry.
Chandan K. Mishra, A. K. Sood and Rajesh Ganapathy, Site-Specific Colloidal Crystal Nucleation by Template-enhanced Particle
Transport, Proceedings of
National Academy of Sciences (PNAS), U.S.A. vol 113 (43), 12094 (2016)"
http://www.thehindu.com/sci-tech/science/Bengaluru-researchers-mimic-nature-to-produce-richer-colour/article16896281.ece
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Noisy contacts in graphene
Prof. Arindam Ghosh: