886 research outputs found
Surface plasmon lifetime in metal nanoshells
The lifetime of localized surface plasmon plays an important role in many
aspects of plasmonics and its applications. In small metal nanostructures, the
dominant mechanism restricting plasmon lifetime is size-dependent Landau
damping. We performed quantum-mechanical calculations of Landau damping for the
bright surface plasmon mode in a metal nanoshell. In contrast to the
conventional model based on the electron surface scattering, we found that the
damping rate decreases as the nanoshell thickness is reduced. The origin of
this behavior is traced to the spatial distribution of plasmon local field
inside the metal shell. We also found that, due to interference of electron
scattering amplitudes from nanoshell's two metal surfaces, the damping rate
exhibits pronounced quantum beats with changing shell thickness.Comment: 9 pages, 4 Figure
Spectroscopic studies of fractal aggregates of silver nanospheres undergoing local restructuring
We present an experimental spectroscopic study of large random colloidal
aggregates of silver nanoparticles undergoing local restructuring. We argue
that such well-known phenomena as strong fluctuation of local electromagnetic
fields, appearance of "hot spots" and enhancement of nonlinear optical
responses depend on the local structure on the scales of several nanosphere
diameters, rather that the large-scale fractal geometry of the sample.Comment: 3.5 pages, submitted to J. Chem. Phy
Voltage dip immunity aspects of power-electronic equipment : recommendations from CIGRE/CIRED/UIE JWG C4.110
This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of powerelectronic equipment are considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available
PENERAPAN HARGA POKOK PRODUKSI MENGGUNAKAN METODE FULL COSTING DALAM MENENTUKAN HARGA JUAL PRODUK SEBAGAI INFORMASI KEUANGAN BAGI PERUSAHAAN (Studi Kasus Pada UD. Konveksi Dua Putra Lombok Barat)
This research aims to find out the application of the cost of goods manufactured by using the full costing method in determining the selling price of products (list price) as company financial information. The types and data source used in this research is primary data that was obtained from the interview to the Umkm (Small Micro Medium Enterprises) and secondary data got from the company's financial report. The data-collection technique in this research is using interviews and documentation. The data analysis technique uses the cost of goods manufacture with full costing methods and for product selling price (list price) use cost-plus pricing. In this study, the results are being acquired in defining the cost of goods manufactured uses the full costing method are more precise and accurate because the full costing method imposes all costs incurred by the company in making these products. The calculations use the cost-plus pricing as the selling price becomes clearer and precise in determining the selling price and profit expected by the company
Mesoscopic Cooperative Emission From a Disordered System
We study theoretically the cooperative light emission from a system of classical oscillators confined within a volume with spatial scale, , much
smaller than the radiation wavelength, . We assume
that the oscillators frequencies are randomly distributed around a central
frequency, , with some characteristic width, . In
the absence of disorder, that is , the cooperative emission spectrum
is composed of a narrow subradiant peak superimposed on a wide superradiant
band. When , we demonstrate that if is large enough, the
subradiant peak is not simply broadened by the disorder but rather splits into
a system of random narrow peaks. We estimate the spectral width of these peaks
as a function of , and . We also estimate the
amplitude of this mesoscopic structure in the emission spectrum.Comment: 25 pages including 6 figure
Nanoplasmonic Renormalization and Enhancement of Coulomb Interactions
Nanostructured plasmonic metal systems are known to enhance greatly variety
of radiative and nonradiative optical processes, both linear and nonlinear,
which are due to the interaction of an electron in a molecule or semiconductor
with the enhanced local optical field of the surface plasmons. Principally
different are numerous many-body phenomena that are due to the Coulomb
interaction between charged particles: carriers (electrons and holes) and ions.
These include carrier-carrier or carrier-ion scattering, energy and momentum
transfer (including the drag effect), thermal equilibration, exciton formation,
impact ionization, Auger effects, etc. It is not widely recognized that these
and other many-body effects can also be modified and enhanced by the
surface-plasmon local fields. A special but extremely important class of such
many-body phenomena is constituted by chemical reactions at metal surfaces,
including catalytic reactions. Here, we propose a general and powerful theory
of the plasmonic enhancement of the many-body phenomena resulting in a closed
expression for the surface plasmon-dressed Coulomb interaction. We illustrate
this theory by computing this dressed interaction explicitly for an important
example of metal-dielectric nanoshells, which exhibits a reach resonant
behavior in both the magnitude and phase. This interaction is used to describe
the nanoplasmonic-enhanced Foerster energy transfer between nanocrystal quantum
dots in the proximity of a plasmonic nanoshell. Catalysis at nanostructured
metal surfaces, nonlocal carrier scattering and surface-enhanced Raman
scattering are discussed among other effects and applications where the
nanoplasmonic renormalization of the Coulomb interaction may be of principal
importance
Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles
We have shown within the quasistatic approximation that the giant
fluctuations of local electromagnetic field in random fractal aggregates of
silver nanospheres are strongly correlated with a local anisotropy factor S
which is defined in this paper. The latter is a purely geometrical parameter
which characterizes the deviation of local environment of a given nanosphere in
an aggregate from spherical symmetry. Therefore, it is possible to predict the
sites with anomalously large local fields in an aggregate without explicitly
solving the electromagnetic problem. We have also demonstrated that the average
(over nanospheres) value of S does not depend noticeably on the fractal
dimension D, except when D approaches the trivial limit D=3. In this case, as
one can expect, the average local environment becomes spherically symmetrical
and S approaches zero. This corresponds to the well-known fact that in trivial
aggregates fluctuations of local electromagnetic fields are much weaker than in
fractal aggregates. Thus, we find that, within the quasistatics, the
large-scale geometry does not have a significant impact on local
electromagnetic responses in nanoaggregates in a wide range of fractal
dimensions. However, this prediction is expected to be not correct in
aggregates which are sufficiently large for the intermediate- and
radiation-zone interaction of individual nanospheres to become important.Comment: 9 pages 9 figures. No revisions from previous version; only figure
layout is change
Metal nanofilm in strong ultrafast optical fields
We predict that a metal nanofilm subjected to an ultrashort (single
oscillation) optical pulse of a high field amplitude at
normal incidence undergoes an ultrafast (at subcycle times ) transition to a state resembling semimetal. Its reflectivity is
greatly reduced, while the transmissivity and the optical field inside the
metal are greatly increased. The temporal profiles of the optical fields are
predicted to exhibit pronounced subcycle oscillations, which are attributed to
the Bloch oscillations and formation of the Wannier-Stark ladder of electronic
states. The reflected, transmitted, and inside-the-metal pulses have non-zero
areas approaching half-cycle pulses. The effects predicted are promising for
applications to nanoplasmonic modulators and field-effect transistors with
petahertz bandwidth
Semimetallization of dielectrics in strong optical fields
At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics
Forced Synchronization of Spaser by an External Optical Wave
We demonstrate that when the frequency of the external field differs from the
lasing frequency of an autonomous spaser, the spaser exhibits stochastic
oscillations at low field intensity. The plasmon oscillations lock to the
frequency of the external field only when the field amplitude exceeds a
threshold value. We find a region of values of the external field amplitude and
the frequency detuning (the Arnold tongue) for which the spaser synchronizes
with the external wave
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