246 research outputs found
Robust Subnanometric Plasmon Ruler by Rescaling of the Nonlocal Optical Response
We present the optical response of two interacting metallic nanowires calculated for separation
distances down to angstrom range. State-of-the-art local and nonlocal approaches are compared with
full quantum time-dependent density functional theory calculations that give an exact account of nonlocal
and tunneling effects. We find that the quantum results are equivalent to those from classical approaches
when the nanoparticle separation is defined as the separation between centroids of the screening charges.
This establishes a universal plasmon ruler for subnanometric distances. Such a ruler not only impacts the
basis of many applications of plasmonics, but also provides a robust rule for subnanometric metrology
Total Polarisation Conversion in Two-dimensional Electron System under Cyclotron Resonance Conditions
The polarisation conversion of a linear polarised electromagnetic wave
incident onto a two-dimensional (2D) electron system at an angle is
theoretically studied. We consider the 2D system located at the interface
between two dielectric media with different dielectric constants. An external
dc magnetic field is assumed to be directed along the normal to the 2D electron
layer. In such a configuration the cyclotron-polaritons (CPs) in 2D electron
system can be excited with the frequencies in the vicinity of the cyclotron
frequency. Under the CPs excitation the resonance polarisation conversion of
electromagnetic wave greatly increases in the system. In the absence of the
electron scattering in 2D system, the polarisation conversion reaches 100% at a
certain value of the angle of incidence which is more than the total reflection
angle. Extremely high polarisation conversion takes place in a quite wide range
of variation of the angle of incidence. High polarisation conversion efficiency
(above 80%) remains when the actual electron scattering in the 2D system on
GsAs is taken into account. The considered phenomena may be taken up in
polarisation spectroscopy of 2D electron systems.Comment: 7 pages, 5 Postscript figure
Tunable Plasmon Molecules in Overlapping Nanovoids
Coupled and shape-tailored metallic nanoparticles are known to exhibit
hybridized plasmon resonances. This Letter discuss the optical properties of a
complementary system formed by overlapped nanovoid dimers buried in gold and
filled with silica. This is an alternative route for plasmon engineering that
benefits from vanishing radiation losses. Our analysis demonstrates the
possibility of designing artificial plasmon molecules on the basis of void
plasmon hybridization, which allows fine mode tuning by varying the overlap
between voids. The proposed structures could find application to both signal
processing through buried optical elements and tunable-plasmon biosensing.Comment: 4 pages, 4 figure
Controlling light-with-light without nonlinearity
According to Huygens' superposition principle, light beams traveling in a
linear medium will pass though one another without mutual disturbance. Indeed,
it is widely held that controlling light signals with light requires intense
laser fields to facilitate beam interactions in nonlinear media, where the
superposition principle can be broken. We demonstrate here that two coherent
beams of light of arbitrarily low intensity can interact on a metamaterial
layer of nanoscale thickness in such a way that one beam modulates the
intensity of the other. We show that the interference of beams can eliminate
the plasmonic Joule losses of light energy in the metamaterial or, in contrast,
can lead to almost total absorbtion of light. Applications of this phenomenon
may lie in ultrafast all-optical pulse-recovery devices, coherence filters and
THz-bandwidth light-by-light modulators
Nanofluidic Refractive-Index Sensors Formed by Nanocavity Resonators in Metals without Plasmons
Nanocavity resonators in metals acting as nanofluidic refractive-index sensors were analyzed theoretically. With the illumination of transverse electric polarized light, the proposed refractive index sensor structure acts as a pure electromagnetic resonator without the excitation of surface plasmons. The reflected signal from the nanocavity resonators can be very sensitive to the refractive index of the fluids inside the nanocavities due to the enhancement of the electric field of the resonant mode inside the cavities. Such a sensor configuration can be a useful tool for probing the refractive index change of the fluid inside the nanocavities using the spectral, angular or intensity interrogation schemes. The wavelength sensitivity of 430 nm/RIU, angular sensitivity of 200–1,000 deg/RIU and intensity sensitivity of 25.5 RIU−1 can be achieved in the proposed sensor configuration
High‐Color‐Purity Subtractive Color Filters with a Wide Viewing Angle Based on Plasmonic Perfect Absorbers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110824/1/adom201400533.pd
Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals
A metallic dielectric photonic crystal with solar broadband, omni-directional, and tunable selective absorption with high temperature stable (1000 °C, 24 hrs) properties is fabricated on a 6” silicon wafer. The broadband absorption is due to a high density of optical cavity modes overlapped with an anti-reflection coating. Results allow for large-scale, low cost, and efficient solar-thermal energy conversion.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-FG02-09ER46577
Theoretical realization of an ultra-efficient thermal-energy harvesting cell made of natural materials
10.1039/c3ee41512kEnergy and Environmental Science6123537-354
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