151 research outputs found
Plasmonic atoms and plasmonic molecules
The proposed paradigm of plasmonic atoms and plasmonic molecules allows one
to describe and predict the strongly localized plasmonic oscillations in the
clusters of nanoparticles and some other nanostructures in uniform way.
Strongly localized plasmonic molecules near the contacting surfaces might
become the fundamental elements (by analogy with Lego bricks) for a
construction of fully integrated opto-electronic nanodevices of any complexity
and scale of integration.Comment: 30 pages, 16 figure
Local field topology behind light localization and metamaterial topological transitions
We revisit the mechanisms governing the sub-wavelength spatial localization
of light in surface plasmon polariton (SPP) modes by investigating both local
and global features in optical powerflow at SPP frequencies. Close inspection
of the instantaneous Poynting vector reveals formation of optical vortices -
localized areas of cyclic powerflow - at the metal-dielectric interface. As a
result, optical energy circulates through a subwavelength-thick 'conveyor belt'
between the metal and dielectric where it creates a high density of optical
states (DOS), tight optical energy localization, and low group velocity
associated with SPP waves. The formation of bonding and anti-bonding SPP modes
in metal-dielectric-metal waveguides can also be conveniently explained in
terms of different spatial arrangements of localized powerflow vortices between
two metal interfaces. Finally, we investigate the underlying mechanisms of
global topological transitions in metamaterials composed of multiple metal and
dielectric films, i.e., transitions of their iso-frequency surfaces from
ellipsoids to hyperboloids, which are not accompanied by the breaking of
lattice symmetry. Our analysis reveals that such global topological transitions
are governed by the dynamic local re-arrangement of local topological features
of the optical interference field, such as vortices and saddle points, which
reconfigures global optical powerflow within the metamaterial. These new
insights into plasmonic light localization and DOS manipulation not only help
to explain the well-known properties of SPP waves but also provide useful
guidelines for the design of plasmonic components and materials for a variety
of practical applications.Comment: 25 pages, 9 figures, Ch. 8 of Singular and Chiral Nanoplasmonics
(S.V. Boriskina and N.I. Zheludev Eds.) Pan Stanford, Singapore, 201
A calibration method for broad-bandwidth cavity enhanced absorption spectroscopy performed with supercontinuum radiation
An efficient calibration method has been developed for broad-bandwidth cavity enhanced absorption spectroscopy. The calibration is performed using phase shift cavity ring-down spectroscopy, which is conveniently implemented through use of an acousto-optic tunable filter (AOTF). The AOTF permits a narrowband portion of the SC spectrum to be scanned over the full high-reflectivity bandwidth of the cavity mirrors. After calibration the AOTF is switched off and broad-bandwidth CEAS can be performed with the same light source without any loss of alignment to the set-up. We demonstrate the merits of the method by probing transitions of oxygen molecules O-2 and collisional pairs of oxygen molecules (O-2)(2) in the visible spectral range
Fluorescent carbon dioxide indicators
Over the last decade, fluorescence has become the dominant tool in biotechnology and medical imaging. These exciting advances have been underpinned by the advances in time-resolved techniques and instrumentation, probe design, chemical / biochemical sensing, coupled with our furthered knowledge in biology. Complementary volumes 9 and 10, Advanced Concepts of Fluorescence Sensing: Small Molecule Sensing and Advanced Concepts of Fluorescence Sensing: Macromolecular Sensing, aim to summarize the current state of the art in fluorescent sensing. For this reason, Drs. Geddes and Lakowicz have invited chapters, encompassing a broad range of fluorescence sensing techniques. Some chapters deal with small molecule sensors, such as for anions, cations, and CO2, while others summarize recent advances in protein-based and macromolecular sensors. The Editors have, however, not included DNA or RNA based sensing in this volume, as this were reviewed in Volume 7 and is to be the subject of a more detailed volume in the near future
Relevance of the diploma section "Civil protection"
На сьогоднішньому етапі реформування вищої освіти навчальна дисципліна «Цивільний захист» вже не є нормативною і виключена з навчальних планів у вищих навчальних закладах, у тому числі технічного профілю. Але соціально-економічна ситуація в країні, нажаль, ускладнюється. Тому зростає необхідність і важливість питань захисту населення в умовах надзвичайних ситуацій.The discipline "Civil Protection" is not normative any more and excluded from the curriculum in higher educational institutions, including the technical profile at the present stage of reforming higher education. However, unfortunately, the socio-economic situation in the country is becoming more complicated. In these conditions, the need and importance of protecting the population in emergency situations is increasing
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