Quantum Phenomena in nanostructures

Quantum kisses between optical nanoantennas

Fig. 2. Electric near-field distribution in the proximity of two metallic nanoantennas at resonance. On the left, a single rod-like metallic nanoantenna 300 nm long and 100 nm wide shows the typical dipolar pattern localizing the field at the antenna extremities and enhancing the amplitude up to 16 times. On the right, a gap-nanoantenna formed by the same nanorods are located in close proximity at a separation of 10 nm, further localizing the field at the gap when illuminated in resonance and increasing the field-enhancement up to 70 due to the strong Coulomb interaction at the gap.The wave nature of light expresses itself in the propagation all over space, showing an intrinsic limitation to be localized beyond the so-called diffraction limit which is of the order of half the wavelength of the photons propagating. However when interacting with matter, light often gets reflected, diffracted, scattered or absorbed depending on the interactions and excitations induced in the material.Fig. 3. Schematics of the electron tunneling produced in a gap. When the separation between two particles is subnanometric, electrons can tunnel forth and back at each optical cycle triggered out by a light pulse. The quantum tunneling through the gap modifies the optical response of the whole antenna. engths, between 450 nm and 800 nm, metals interact with electromagnetic waves producing a variety of optical effects. The conduction electrons that constitute the metal can oscillate rigidly at certain optical frequencies that depend on the electron density. Furthermore, when metals are physically bounded by surfaces and interfaces as it is usually the case in nanoparticles and nanostructures, the oscillations of the electron charge density at the surfaces show resonant localized modes so-called surface plasmons. The excitation of these surface plamons by light produces a localization and enhancement of the visible light at the surface of the metal at distances of a few nanometers, well below the diffraction limit, thus acting metallic nanostructures as resonant emitters or receptors of light. This is the reason why metallic nanostructures are often referred to as optical nanoantennas.

Fig. 4. (a) Extinction cross section and (b) near-field enhancement at the gap of two metallic nanoparticles as a function of separation distance between the particles calculated within a classical formalism. (c) and (d) show the same calculation as in (a) and (b) with use of a quantum-corrected model [3] to describe the interaction between nanoparticles. The differences of the results between the two approaches are clear both in the far-field as well as in the near-field.An example of the simplest optical nanoantenna one can think of is shown in Fig. 1a. A metallic nanoparticle enhances both the absorption and the scattering of visible light acting as an isotropic optical nanoantenna. The spectrum of scattering and emission (Fig.1b) shows a distinctive resonance or antenna mode sustained by the excitation of localized surface plasmons.

Fig. 1. (a) Schematics of a metallic nanoparticle responding to light of energy ħν linearly polarized by means of the excitation of a localized dipolar surface plasmon at the particle. This surface plasmon either emits at the resonance frequency or is absorbed by phonon excitation. (b) Scattering, absorption and extinction (scattering+absorption) coefficients Qscat, Qabs and Qext respectively, of a 5 nm metallic nanoparticle showing a resonant response at an energy of ħω=8.5eV.

In the last years, the development of sophisticated fabrication techniques that range from electron beam lithography to wet chemistry synthesis, together with the improvement of optical characterization techniques allowing for accessing far-field as well as near-field properties in the nanoscale have made possible to study ultrafast processes and nonlinear phenomena induced by intense light pulses. In parallel, new theoretical frameworks have been developed to describe the main features of the complex physical processes involved in the interaction between light and matter, boosting tremendously the field of plasmonics .

Springer Quantum Phenomena in Clusters and Nanostructures (Springer Series in Cluster Physics)
Book (Springer)
  • Used Book in Good Condition

Language clarification (to me) request

by gerundergrund

i'll give you +1 for sort of funny < - > 06/26 22:46:47
invisibility cloak via metamaterials, negative index materials, and plasmonic nanostructures...ok then
spare me the details
def regurgs please? :
"invisibility via metamaterials" >>>cheeky designatory reference terminology selection, because what's interdicted is in classified genre- wise as "metamaterial"--the light photons--non material so meta material. Like saying "I'm shooting bullets at him" and not "I'm shooting my gun at him". That's my understanding

Nanotubes Increase Solar PV Conductivity 100 Million-Fold  — Sourceable
Carbon-based nanostructures are already being used as materials in solar cells with increasing frequency, yet their ability to enhance electrical performance has thus far been hampered by limited ability to assemble orderly networks using the materials.

Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII (Proceedings of Spie)
Book (Society of Photo Optical)
Related Posts