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Photonic Metamaterials
Published in Pankaj K. Choudhury, Metamaterials, 2021
Recently, the field of plasmonics has been the subject of extensive research, giving rise to a perfect match of electronics and photonics at the nanoscale. Plasmons are collective oscillations of charge carriers in metal and semiconductors. The former can either be localized as the eigen-mode of nanocomposite or propagate over extended surfaces. Doing so, the phenomenon of sub-wavelength light confinement, thereby resulting in giant electric field enhancement into specific nano-sized regions (called hotspots), is enabled [1]. These attractive features open wide avenues for a range of applications, such as optical sensing [2,3], quantum electrodynamics [4,5], non-linear optics [6,7], photovoltaic technologies [8], and medical diagnosis and treatment [9,10]. A deep physical insight has been gained to engineer plasmonic devices with tunable plasmon frequencies and associated electric field spatial distribution. This can be reached by designing different metallic micro- and nanostructures [11–14] and by exploiting widely studied phenomena, such as Fano interactions [15,16] with other excitations, plasmon hybridization [17,18] and electromagnetically induced transparency [19,20].
Amplification of Surface Plasmons
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
There is a growing interest in plasmonics in recent years, on one hand motivated by the need to understand and control the behavior of light below the diffraction limit, and on the other by its potential applications in devices, sensing, giant field enhancement, negative index materials, and many others. Assuming that the appropriate materials will be found, or designed, along with practical structures, it is expected that the field of plasmonics has a potential to also revolutionalize the microelectronics industry. Currently, the main issue that halts the application of plasmonics are losses in metals that affect the performance of every plasmonic structure. At present, main conventional plasmonic materials used in plasmonics are gold and silver because of their relatively small ohmic losses when compared with other metals. However, the existing losses in those materials are still one of the major problems in using those metals in plasmonics.
Metal Plasmonics
Published in Myeongkyu Lee, Optics for Materials Scientists, 2019
Photovoltaics, which refers to the conversion of sunlight to electricity using solar cells, is a promising technology that may allow the production of electric power on a very large scale. Plasmons are free-electron oscillations in a metal that enables light to be manipulated at the nanoscale. The ability of plasmons to guide and confine light opens up new design possibilities for solar cells.62–71 Photovoltaics can make a considerable contribution to solving the energy problem that our society will face in the next generation. At present, commercial photovoltaic cells are mostly based on crystalline silicon wafers with thicknesses of 150–300 μm, and most of the price of solar cells is due to the costs of silicon materials and processing. To be competitive with fossil-fuel technologies, the cost needs to be reduced by a factor of 2–5. In this respect, there is great interest in thin film solar cells, which are made from a wide variety of semiconductors including amorphous and polycrystalline Si, GaAs, CdTe, and CuInSe2, as well as organic and perovskite semiconductors. A key advantage of such thin devices is the small amount of material required. However, the reduced thickness should not come at the expense of performance. The most fundamental problem incurred by reduced thickness is poorer light absorption, which is a disadvantage that should be overcome through an approach called “light trapping.”
Sensitivity enhancement of fiber surface plasmon resonance (SPR) sensor based upon a gold film-hexagonal boron nitride—molybdenum disulfide structure
Published in Instrumentation Science & Technology, 2022
Haizhou Zheng, Jiayang Yang, Qi Wang, Bin Feng, Ruifeng An
Surface plasmon resonance refers to the phenomenon caused by the coupling between polarized light and metal surface plasmon waves, which greatly reduces the reflected light intensity at the interface between metal and medium, thus forming a resonance trough.[6–9] The position of the resonant trough changes with the refractive index (RI) of the medium.[10] When a marker in the solution binds to the sensor, the refractive index of the medium changes, causing a migration in the SPR trough that may be monitored.[5] However, due to the low photoelectric conversion efficiency, the ordinary instant plasmon resonance sensor cannot fully absorb flooded light and is unable determine small molecules and low concentrations.[11]
Surface plasmons in metamaterial heterostructures
Published in Waves in Random and Complex Media, 2021
Recently, the field of plasmonics has been an object of extensive research, giving rise to a perfect match of electronics and photonics at the nanoscale. Plasmons are collective oscillations of charge carriers in metal and semiconductor. The former can either be localized as eigen-mode of the nanocomposite or propagate over extended surfaces. Doing so, the phenomenon of subwavelength light confinement and a giant electric field enhancement into specific nano-sized regions, called hotspots [1] is enabled. The described attractive features open the wide avenues for a range of applications, such as optical sensing [2,3], quantum electrodynamics [4,5], nonlinear optics [6,7], photovoltaic technologies [8], and medical diagnosis and treatment [9,10]. A deep physical insight has been gained to engineer plasmonic devices with tunable plasmon frequencies and associated electric field spatial distribution. This can be reached by designing different metallic micro- and nanostructures [11–14] and exploiting widely studied phenomena as Fano interactions [15,16] with other excitations, plasmon hybridization [17,18], and electromagnetically induced transparency [19,20].
The influence of a dielectric spacer layer on the morphological, optical and electrical properties of self-dewetted silver nanoparticles
Published in Phase Transitions, 2021
Leila Manai, Béchir Dridi Rezgui, Damien Barakel, Philippe Torchio, Olivier Palais, Olfa Messaoudi, Arwa Azhary, Feriel Bouhjar, Brahim Bessais
The collective oscillations of electrons in metal nanoparticles excited by incident light lead to the formation of polarization charges on the particle surface, i.e. origin of the localized surface plasmons. Plasmonic effect consists in trapping of the incident light by plasmons due either to absorption and (or) scattering depending upon the nanoparticle size. The absorption by plasmons dominates for metallic particles with a size much smaller than the plasmon wavelength of light. However, as the particle size increases, plasmonic scattering prevails for light wavelength around the plasmonic resonance. The angular spread of light is accompanied by an enhancement in path length in silicon substrate and thereby increased absorption and generation of electron–hole pairs. Finally, scattering process must lead to enhanced absorption of light in the substrate and hence to a predictable conversion efficiency improvement, which will be discussed in the next section.