Abstract. To achieve efficient light control at subwavelength dimensions, plasmonic and all-dielectric nanoparticles have been utilized both as a single element as well as in the arrays. Here we study 2D periodic nanoparticle arrays (metasurfaces) that support lattice resonances near the Rayleigh anomaly due to the electric dipole (ED) and magnetic dipole (MD) resonant coupling between the nanoparticles. Silicon and core-shell particles are considered. We demonstrate for the first time that, choosing of lattice periods independently in each mutual-perpendicular direction, it is possible to achieve a full overlap between the ED-lattice resonance and MD resonances of nanoparticles in certain spectral range and to realize the resonant lattice Kerker effect (resonant suppression of the scattering or reflection). At the effect conditions, the strong suppression of light reflectance in the structure is appeared due to destructive interference between electromagnetic waves scattered by ED and MD moments of every nanoparticle in the backward direction with respect to the incident light wave. Influence of the array size on the revealed reflectance and transmittance behavior is discussed. The resonant lattice Kerker effect based on the overlap of both ED and MD lattice resonances is also demonstrated.Both plasmonic and all-dielectric nanostructures have been proposed for efficient manipulation of light at the nanoscale [1][2][3], with particular interest to be applied in ultra-thin functional elements, so-called metasurfaces [4][5][6], and in particular to control reflection from the material interfaces [7,8] and to improve photovoltaic properties [9][10][11]. With the typical linear dimensions of 100-200 nm, high-refractive-index (silicon) nanoparticles induce enhanced electric and magnetic moments and support Mie resonances in the visible spectral range as it has been first shown theoretically in [12] and then experimentally proved in [13] (see also [14,15]). Utilizing high-refractive-index nanoparticles gives an opportunity to obtain magnetic optical response without using metal inclusions such as split-ring resonators or core-shell particles, and avoid high non-radiative optical losses associated with metals [16]. Such all-dielectric nanostructures, for instance, nanoparticle arrays (metasurfaces), demonstrate a variety of unique effects, and in particular suppression of reflection in a pre-defined direction [17,18]. As has been shown in the earlier work [19], if electric and magnetic polarizabilities of a nanoparticle are equal each other in magnitude and phase (the first Kerker condition), light scattering from this nanoparticle is suppressed in the backward direction, and recently, it is referred as a Kerker effect. For silicon spherical nanoparticle array, ED and MD do not overlap, and only non-resonant Kerker effect is possible: antireflective properties are observed at wavelength either larger than the wavelength of the magnetic dipole (MD) resonance [12] or smaller than the wavelength of the electric dipole (ED...

We study emission of photoelectrons from plasmonic nanoparticles into surrounding matrix. We consider two mechanisms of the photoelectric effect from nanoparticles -surface and volume ones, and use models of these two effects which allow us to obtain analytical results for the photoelectron emission rates from nanoparticle. Calculations have been done for the step potential at surface of spherical nanoparticle, and the simple model for the hot electron cooling have been used. We highlight the effect of the discontinuity of the dielectric permittivity at the nanoparticle boundary in the surface mechanism, which leads to substantial (by ~5 times) increase of photoelectron emission rate from nanoparticle compared to the case when such discontinuity is absent. For plasmonic nanoparticle, a comparison of two mechanisms of the photoeffect was done for the first time and showed that surface photoeffect, at least, does not concede the volume one, which agrees with results for the flat metal surface first formulated by Tamm and Schubin in their pioneering development of quantummechanical theory of photoeffect in 1931. In accordance with our calculations, this predominance of the surface effect is a result of effective cooling of hot carriers, during their propagation from volume of the nanoparticle to its surface in the scenario of the volume mechanism. Taking into account both mechanisms is essential in development of devices based on the photoelectric effect and in usage of hot electrons from plasmonic nanoantenna.1I.

Abstract:The ongoing quest for ultra-compact optical devices has reached a bottleneck due to the diffraction limit in conventional photonics. New approaches that provide subwavelength optical elements, and therefore lead to miniaturization of the entire photonic circuit, are urgently required. Plasmonics, which combines nanoscale light confinement and optical-speed processing of signals, has the potential to enable the next generation of hybrid information-processing devices, which are superior to the current photonic dielectric components in terms of speed and compactness. New plasmonic materials (other than metals), or optical materials with metal-like behavior, have recently attracted a lot of attention due to the promise they hold to enable low-loss, tunable, CMOScompatible devices for photonic technologies. In this review, we provide a systematic overview of various compact optical modulator designs that utilize a class of the most promising new materials as the active layer or corenamely, transparent conducting oxides. Such modulators can be made low-loss, compact, and exhibit high tunability while offering low cost and compatibility with existing semiconductor technologies. A detailed analysis of different configurations and their working characteristics, such as their extinction ratio, compactness, bandwidth, and losses, is performed identifying the most promising designs.