Thesis and Guide details:
Details of CSIR Fellowship/ Associateship held, if any or from other sources/ agencies.
Significant foreign assignments:
(a) Significant contributions to science and/ or technology development by the nominee
based on the work done in India during most part of last 5 years:
Since 2011, Dr. Ramakrishna has developed a unique programon developing novel kinds
metamaterials functioning at optical to infra-red frequencies. His works, which comprises a major portion of
the Indian output in the area of Metamaterials, have been important contributions to the field. Being one of
the pioneers working in this field since 2001, he has concentrated in recent years on applications and
technologies of metamaterials and plasmonic nanostructured thin films. Primary among the recent
developments, are the anisotropic metamaterial optical fibers [70, 79] {5}, which are new forms of
anisotropic metamaterials in the cylindrical geometry, frequency selective multiband metamaterial perfect
absorbers for bolometric and hyperspectral imaging applications [47, 51 56, 61, 62, 66, 75], nonlinear and
switchable metamaterial absorbers [68, 69] {3}, and periodically patterned columnar plasmonic thin films
[52, 55, 65, 72] . Each development has required innovations in micro- and nanostructuring processes, with
many of them patented (see list of patents applied for). In terms of scholarship, his review on metamaterials
in 2005 (cited 707 times) and research monograph published in 2009 (cited 228 times) are highly utilized and
appreciated in the field.
Anisotropic metamaterial optical fibers [74,79]: Nanoporous alumina microtubes were developed to form
anisotropic metamaterials in the cylindrical geometry, . When the nanopores are filled with a plasmonic
metal, hyperbolic anisotropy is realized. The optical modes supported in these fibers are exotic and described
by Bessel functions of imaginary and complex orders, which have been noted for the first time in the context
of optical guidance. Further, the Nanoporous alumina microtubes have enhanced thermal properties that are
proposed for micro heat exchangers with highly enhanced wetting, pool boiling and heat conductance rates.
This new system has much potential to be technologically disruptive and create many new applications
Optical - Infrared metamaterial perfect absorbers: Extremely thin (subwavelength) high efficiency
absorbers based on metamaterial structures have been developed [47, 51, 56, 61, 62, 66, 75]. These
structures have absorption greater than 95% over selected bands that are determined by the metamaterial
structural sizes. Large absorption over multiple bands at visible[68, 75, 76] to long wave infrared
wavelengths [61, 62, 66] have been realized. The nominee has contributed to the fundamental understanding
of these absorbers, described them as highly impedance matched patch antenna arrays [47, 61, 62] and has
been highly cited for this understanding (over 120 citations). He has developed infrared absorbers that are
transparent for visible light, which allows for multiplexing applications at different wavelengths [61] as well
as flexible substrates [66]. The switchable absorbers obtained by temperature sensitive vanadium dioxide
thin films embedded in the transparent absorbers [69] have enabled an thermal to optical valve, an essential
component of an infrared thermal imaging focal plane array. This work has been developed specifically for
the DRDO. The selective multiband absorbers are expected to enable futuristic hyperspectral imaging with
uncooled devices. Nonlinear and switchable metamaterials [68, 69]: The nominee has made fundamental contributions to the
present ‘hot’ area of metamaterial nonlinearities by demonstrating metamaterial nonlinearities which arise
specifically due to the geometry of the structures and may not be present in the constituent materials.
(b) Impact of the contributions in the field concerned:
Prof. Ramakrishna has published over 80 papers in the area of metamaterials and plasmonic
nanostructured materials. His work has drawn enormous attention from the scientific community and has
been highly cited with over 3850 citations and an h-index of 19 (source: Google scholar). He has also
concentrated on technology development, filing 9 patents in the past five years. He has proposed for the first
time several concepts such as: the mechanisms of imaging with super-resolution with negative refractive
index lenses [10, 14, 16, 19] (totalling 1093 citations) the use of amplifying media in metamaterial and
plasmonic structures [17] (292 citations), the use of transformation optics to perfect lenses of negative index
materials [22](298 citations), first design for optical frequency metamaterials [31] (194 citations),
demonstration of negative refraction in acoustic metamaterials [31](150 citations), a proper explanation of
the choice of the negative root for the wave vector in negative index media [24] (52 citations), coherent
control of metamaterials by atomic / molecular resonances [34, 38, 41] (38 citations) and so on. His work on
the traversal times for light in dispersive media [26, 35] has solely motivated at least 8 research papers from
various international groups.
Among the work in the past 5 years, his work on perfectly absorbing metamaterials as highly
impedance matched antennas at inflated and optical frequencies [47, 51, 56, 61, 62, 66, 75] has drawn much
attention (over 135 citations). One of these papers [56] received an honorable mention in the 2015 Journal of
Optics research excellence award and was listed in the year of light collection of the Journal of Optics. These
works lay the route to the development of highly sensitized and spectrally selective focal plane arrays for
thermal hyper spectral images for the DRDO (IRDE, Dehradun), which is being taken up through their
nanophotonics program. His work on plasmonic and metamaterial resonant structures for surface enhanced
Raman scattering [43, 48, 49] (SERS) (21 citations) is now being taken up with the Department of Atomic
Energy for applications to the Raman spectroscopy of actinide series elements. Dr. Ramakrishna's work on
optical properties of plasmonic nanostructures has also drawn attention [45, 50, 58, 60] (30 citations),
particularly the demonstration of broadband extraordinary transmittance in highly singular checkerboard
plasmonic structures [45] (15 citations). His recent work on fingerprint visualization by depositing columnar
thin films and fluorescent dyes [52] (7 citations) was tabled in the 17th Triennial Interpol International
Forensic sciences manager’s symposium report on recent forensic techniques developed during 2010-2013.
His scholarship on metamaterials is highly recognized, with his comprehensive review in the Reports
on Progress in Physics [23] in 2005, and subsequently his book in 2009 on negative refractive index
materials being the reference of choice for beginning graduate students in this area of research across the
world. The book received excellent reviews [A.H. Harker, Contemporary Physics, 51 (4), 372-375 (2010)].
These reference works have garnered almost a thousand citations till date. He is one of the few researchers to conduct both theoretical and experimental work simultaneously with a view to developing technologies and
applications throughout.
Places where work of last 5 years has been referred/ cited in Books, Reviews:
Names of the industries in which the technology (ies) has (have) been used :
The achievements already been recognised by Awards by any learned body:
The Awardee a fellow of the Indian National Science Academy/Indian Academy of Sciences/National
Academy of Sciences/Others:
The Awardee delivered invited lecture(s) in India/abroad and/or chaired any scientific
Internatiional Conference Symposium:
List of Awardee's 10 most significant publications.
List of Awardee's 5 most significant publications during the last 5 years
List of Awardee's 5 most significant publications from out of work done in India
during the last five years:
Complete list of publications in standard refereed journals:
Complete list of publications with foreign collaborators (indicating your status
as author):
List of papers published in Conferences /Symposia/ Seminars, etc:
List of the most outstanding Technical Reports/ Review Articles:
Statement regarding collaboration with scientists abroad:
Total number of patents granted in last five years.
Details of Books published: