Impact of plasmonic bowtie nanoantennas and nanocavities on the dynamics of nearby nanoemitters

Metallic nanoparticles exert a strong influence on the electrodynamics and mechanical dynamics of nanoemitters in their vicinity. Transformation optics can provide analytical descriptions and physical insight on these scenarios. As a case of study, we discuss the use of conformal transformation to understand the nonradiative Purcell enhancement and the optical forces experienced by nanoemitters nearby bowtie nanocavities and nanoantennas

Phase reversal technique applied to fishnet metalenses

In this work, the fishnet metamaterial is applied to several converging metalenses by combining the zoning, reference phase, and phase reversal techniques. First, the zoning and reference phase techniques are implemented in several metalenses at 55 GHz ( λ 0 = 5.45 m m ) with a short focal length of 1.5 λ 0 . Then, the phase reversal technique is applied to these metalenses by switching from a concave to a convex profile in order to change the phase distribution inside of them. The designs are evaluated both numerically and experimentally demonstrating that chromatic dispersion (the shift of the position of the focus at different frequencies) is reduced when using the phase-reversed profiles. It is shown how the position of the focus remains at the same location within a relatively broadband frequency range of ~4% around the design frequency without affecting the overall behaviour of the metalenses. The best performance is achieved with the design that combines both reference phase and phase reversal techniques, with an experimental position of the focus of 1.75 λ 0 , reduced side lobes, and a power enhancement of 6.5 dB. The metalenses designed here may find applications in situations where a wideband response and low side lobes are required because of the reduced chromatic aberrations of the focus.This work was partially supported by the Spanish Ministerio de Economía y Competitividad with European Union Fondo Europeo de Desarrollo Regional (FEDER) funds (TEC2014-51902-C2-2-R). Victor Pacheco-Peña is supported by Newcastle University (Newcastle University Research Fellow). Igor V. Minin and Oleg V. Minin were partially supported by the Mendeleev scientific fund of Tomsk State University

High resolution terajets using 3D cuboids

The limit imposed intrinsically by the diffraction of electromagnetic waves has been extensively studied with the aim to improve the performance of microscopy techniques and to obtain subwavelength resolution. Several techniques have been proposed to solve this disadvantage such as metamaterials and microspherical particles, to name a few

Soret fishnet metalens antenna.

At the expense of frequency narrowing, binary amplitude-only diffractive optical elements emulate refractive lenses without the need of large profiles. Unfortunately, they also present larger Fresnel reflection loss than conventional lenses. This is usually tackled by implementing unattractive cumbersome designs. Here we demonstrate that simplicity is not at odds with performance and we show how the fishnet metamaterial can improve the radiation pattern of a Soret lens. The building block of this advanced Soret lens is the fishnet metamaterial operating in the near-zero refractive index regime with one of the edge layers designed with alternating opaque and transparent concentric rings made of subwavelength holes. The hybrid Soret fishnet metalens retains all themeritsof classicalSoret lenses suchas lowprofile, lowcost andeaseofmanufacturing. It is designed for the W-band of themillimeter-waves range with a subwavelength focal lengthFL51.58 mm(0.5l0) aiming at a compact antenna or radar systems. The focal properties of the lens along with its radiation characteristics in a lens antenna configuration have been studied numerically and confirmed experimentally, showing a gain improvement of ,2 dB with respect to a fishnet Soret lens without the fishnet metamaterial.Effort sponsored by Spanish Government under contracts Consolider ‘‘Engineering Metamaterials’’ CSD2008-00066, TEC2011-28664-C02-01. B. O. is sponsored by Spanish Ministerio de Economía y Competitividad under grant FPI BES-2012-054909. M. B. is sponsored by the Spanish Government via RYC-2011-08221. V.P.-P. is sponsored by Spanish Ministerio de Educación, Cultura y Deporte under grant FPU AP-2012-3796. M. N.-C. is supported by the Imperial College Junior Research Fellowship