37 research outputs found
Optical Absorption of Plasmonic Nanoparticles in Presence of a Local Interband Transition
No full textThe influences of a local interband transition on optical absorptions of plasmonic nanoparticles are investigated It is found that the optical absorption associated with a local interband transition is remarkably enhanced because of the presence of a localized surface plasmon resonance on the basis of the quasistatic theory, Mie calculations, and the classical models, the electromagnetic interaction of plasmon- and interband-dipole is studied. It is shown that two modes with different characters are generated because of the strong inherent interaction. As a consequence of this interaction; the two modes are repulsed, and an avoided,crossing zone is constructed where the particle plasmon energy coincides with the energy of a local interband transition. The energies of the two modes are interchanged as the crossing zone traversed
Efficient tunability and circuit model of nested-U nanoresonators in optical metasurfaces
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Optical absorbing origin of chiroptical activity in planar plasmonic metasurfaces
No full textAbstractAs a significant characteristic of many biomolecules, chemical substances, and artificial nanostructures, chirality conduce different types of optical interactions with the spin angular momentum of the impinging light field. Although, chiral arrangement and spatial phase retardation are the key factors for obtaining chirality in three-dimensional (3D) structures, the origin of chirality in the feasible planar structures has not been thoroughly addressed. Here using an intuitive and simple analytical approach, called cross-hybridization model, the essence and properties of the optical chirality of individual planar nanostructures are unveiled. In order to fundamentally address this chirality in terms of circular dichroism (CD), the chiroptical response of a simple dimer composed of the lossy nanoblocks in L-shape arrangement are investigated based on the provided optical interaction and loss effects. The theoretical findings, adequately supported by the numerical calculations, reveal that chiroptical activity occurs predominantly due to handedness-dependent absorption or heating loss in a nanostructured metasurface.</jats:p
Optical Circular Conversion Dichroism via Heterogeneous Planar Nanoplasmonic Metasurface
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Unidirectional ultracompact optical nanoantennas
No full textWe report on a dramatic directionality effect in a simple and ultracompact optical nanoantenna consisting of a pair of interacting plasmonic nanoparticles. We found that the emission from a dipole source positioned close to one of the particles in the pair exhibits an essentially unidirectional radiation pattern for emission wavelengths close to the antiphase hybridized plasmon. We analyze this unique effect in terms of radiation, reception, and reciprocity concepts using electrodynamics simulations and dipole analysis. A forward-backward directionality of similar to 18 dB at 665 nm is obtained for a nanoantenna that consists of two 90 nm wide and 20 nm thick gold nanodisks separated by a 10 nm gap
Unidirectional Ultracompact Optical Nanoantennas
No full textWe report on a dramatic directionality effect in a simple and ultracompact optical nanoantenna consisting of a pair of interacting plasmonic nanoparticles. We found that the emission from a dipole source positioned close to one of the particles in the pair exhibits an essentially unidirectional radiation pattern for emission wavelengths close to the antiphase hybridized plasmon. We analyze this unique effect in terms of radiation, reception, and reciprocity concepts using electrodynamics simulations and dipole analysis. A forward−backward directionality of ∼18 dB at 665 nm is obtained for a nanoantenna that consists of two 90 nm wide and 20 nm thick gold nanodisks separated by a 10 nm gap
