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Desalination and drying
Published in David Thorpe, Solar Energy Pocket Reference, 2018
This new technology is at the experimental stage. Plasmon-mediated solar desalination utilises an aluminium structure that absorbs photons spanning the 200nm–2,500nm wavelength range, and is claimed by researchers12 to be both cheap and ‘clean’. A plasmon is a quantum of plasma oscillation. Just as light consists of photons, the plasma oscillation consists of plasmons. Plasmons play a large role in the optical properties of metals and semiconductors. Light of frequencies below the plasma frequency is reflected by a material because the electrons in the material screen the electric field of the light. Light of frequencies above the plasma frequency is transmitted by a material because the electrons in the material cannot respond fast enough to screen it. In most metals, the plasma frequency is in the ultraviolet, making them shiny (reflective) in the visible range. The plasmon frequency may occur in the mid-infrared and near-infrared region when semiconductors are in the form of nanoparticles with heavy doping.
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Published in Dikshitulu K. Kalluri, Principles of Electromagnetic Waves and Materials, 2017
Note that the phase velocity a becomes negligible for the cold plasma approximation and the electron plasma wave becomes a plasma oscillation at the plasma frequency ωp. A simple way of interpreting the electron plasma wave is to say that the plasma oscillation becomes a longitudinal electron plasma wave when the plasma is considered as warm.
Special Topics
Published in James J Y Hsu, Nanocomputing, 2017
Plasmon is the quantized plasma oscillation, often at optical frequencies. They may couple with a photon to create a quasiparticle called polariton. Photons with frequency below the plasma frequency are reflected. For most metals, the plasma frequency is in the ultraviolet range, making them shiny in the visible light. Some metals, such as copper and gold, have electronic interband transitions absorbing light in the visible range, giving rise to their distinct colors.
Systematic study of phase transformation, wide-to-narrow electronic band transition and optical properties of barium zirconium Oxynitrate: Ab initio calculations
Published in Molecular Physics, 2022
S. S. A. Gillani, Musaddaq Mukhtar, I. Zeba, M. Shakil, Tousif Hussain, Riaz Ahmad
Pristine and doped systems show a noticeable peak at 9.57 eV and non-zero absorption. The absorption curve at 19.27 eV has a significant peak, and the energy loss curve indicates lower energy dissipation (Figure 6(e)). The absorption edge of the N-doped BZO shows that the energy gap is shrinking (red shift). Figure 6(e) illustrates the energy loss function (ELF) for the doped and undoped system. The peaks of the ELF spectrum are referred to as typical energies, and the associated frequency is referred to as plasma frequency. Within this duration, plasma oscillations occur in this energy range (ELF). Lattice sites do not have fixed electrical locations [48–53]. A sharp peak of plasma oscillation for a pure system is identified at 23.42 eV, although this peak shifts for the N2-doped system to lower energy (22.89 eV). One of the primary features of semiconductor materials is the higher ε2 values correlating to lower ELF values. Reflection spectra for undoped and doped systems are illustrated in Figure 6(f). When the doping increases, there is a decline in reflectivity, which results in the shifting of the main peak towards slightly higher energies. By comparing reflection and absorption curves, during a period when the reflection is at its maximum, the absorption is minimum in its value for a given energy value. In comparison with undoped and N2-doped BZO, a small peak is noticed at 0.02 eV, nearly in each optical characteristic (Figure 6), and similar results for CsMgX3 (X = Cl, Br) have been reported in the literature [54].
Dynamics of dust-ion acoustic cnoidal and solitary pulses in a magnetized collisional complex plasma
Published in Waves in Random and Complex Media, 2021
Asmaa Mohamed Abdelghany, Mohammed Shihab, Mahmoud Saad Afify
Thanks to P. K. Shukla who was the pioneer to predict the propagation of the dust acoustic waves (DAWs), which are an analogy to ion-acoustic waves, in 1989 at the First Capri Workshop on Dusty Plasmas [14]. Afterward, this study was published in 1990 then it verified experimentally in 1995 by Barkan et al. [15]. Further, Shukla and Silin documented the evolution of the dust ion-acoustic wave in unmagnetized dusty plasma [16]. DAWs are very low-frequency acoustic waves, i.e less than the plasma oscillation, as the response time of heavy mass dust particles to high-frequency oscillation is very large. The dust grains participate directly in the wave dynamics, however, the electron and ion inertia can be neglected. For the dust ion-acoustic waves (DIAWs), both dust particles and ions are treated as fluid, while the distribution function for electron density is taken into account. This is because the Landau damping due to wave-particle interactions at could be neglected as the phase velocity of DIAWs increased with increasing dust density [17]. The dust particles which added to a low-temperature electron-ion plasma may acquire negative charge as electrons are lighter than ions and it may acquire positive charge in the presence of negative ions. Hence, these particles may lead to an abroad range of wave phenomena[18, 19].
Preparation and properties of a left-handed metamaterial composite
Published in Philosophical Magazine Letters, 2019
Haiyan Li, Yuheng Guo, Zhenhai Li
When the Ag content increases to 50 wt% (exceeding the percolation threshold value), a negative permittivity is observed when a continuous Ag network forms a percolation transition. At this point, plasma oscillation of delocalised electrons in conductive networks causes a negative permittivity behaviour of the YIG/Ag composites. The real part of the permittivity with a Fano-like resonance crosses zero (Figure 4c), where switches from negative to positive at 60 MHz. In order to understand the mechanisms responsible for the negative permittivity and the Fano-like resonance, studies of the impedance of the YIG/Ag composites are described in the following sections.