Quantum antenna arrays: The role of quantum interference on direction-dependent photon statistics

© 2018 American Physical Society. We investigate the role of quantum interference phenomena on the characteristics of the fields radiated by an array of quantum emitters. In analogy to, but distinct from, classical outcomes, we demonstrate that the array geometry empowers control over direction-dependent photon statistics of arbitrary order. Our formulation enables the recognition of configurations providing spatial correlations with no classical counterpart. For example, we identify a system in which the angular distribution of the average number of photons is independent of the number and position of the emitters, while its higher-order photon statistics exhibit a directional behavior. These results extend our understanding of the fields generated by ensembles of quantum emitters, with potential applications to nonclassical light sources

Control of a quantum emitter's bandwidth by managing its reactive power

© 2019 American Physical Society. ©2019 American Physical Society. Reactive power plays a crucial role in the design of small antenna systems, but its impact on the bandwidth of quantum emitters is typically disregarded. Here, we theoretically demonstrate that there is an intermediate domain between the usual weak- and strong-coupling regimes where the bandwidth of a quantum emitter is directly related to the dispersion properties of the reactive power. This result emphasizes that reactive power must be understood as an additional degree of freedom in engineering the bandwidth of quantum emitters. We illustrate the applicability of this concept by revisiting typical configurations of quantum emitters coupled to resonant cavities and waveguides. Analysis of the reactive power in these systems unveils functionalities including the design of efficient but narrow-band photon sources, as well as quantum emitters exhibiting bandwidths narrower than their nonradiative linewidths even under incoherent pumping

Designing the bandwidth of single-photon sources with classical antenna techniques

© 2019 European Association on Antennas and Propagation. We discuss the role of the classical electromagnetic theory concept of reactive interactions on determining the bandwidth of a single-photon source. Typically, quantum emitters operate in the weak-coupling regime where the bandwidth of the emission spectrum is simply proportional to their decay rates. However, we introduce a first-order correction to the emission spectrum, demonstrating that its bandwidth is also directly affected by the dispersion properties of the reactive interactions of the quantum emitter with its environment. This correction is particularly important in the intermediate region bridging the weak and strong coupling regimes. As an example of the applicability of this theory, we study the behaviour of a quantum emitter decaying through a coupled two-cavity system. Our results suggests that this setup could be utilized for the design of efficient, but narrowband single-photon sources

Induction theorem analysis of resonant nanoparticles: Design of a huygens source nanoparticle laser

© 2014 American Physical Society. We propose an advanced formulation of standard antenna theory for the basic investigation and design of resonant nanoparticles. This methodology is based on transforming the original scattering problem into a radiation configuration by invoking the induction theorem. Then applying basic antenna theory principles, such as the suppression of any reactive power, the properties of the resonances are engineered. This nanoantenna approach has been validated by revisiting a number of well-known multilayered core-shell structures. It provides additional important physical insights into how the core-shell structures operate and it enables combinations of different resonant phenomena associated with them, e.g., plasmonic and high-Ï resonances, in an intuitive manner. Its efficacy is demonstrated by designing a multilayered nanoparticle that achieves lasing with a maximum directivity in the forward direction and a null in the backward direction, i.e., a Huygens source nanoparticle laser

Electromagnetic force density in electrically and magnetically polarizable media

The force density induced by electromagnetic fields in electrically and magnetically polarizable media is studied analytically. Different formulations of the force density as a function of field-related quantities, including the spatial derivatives of the fields, gradients of the field intensity, phase gradients, electromagnetic power flow (Poynting vector field), and kinetic momentum flow, are introduced. These formulations retain certain symmetries with respect to the force expressions introduced in previous works for an isolated particle but also point out fundamental differences, such as the suppression of recoil forces, negative radiation pressure, and far-field gradient forces. It is shown how these analytical formulations also provide the necessary means to elucidate the sign of the force density in complex media and how they can assist the design of sources to manipulate clouds of particles. The theory is illustrated with numerical examples of an insulated Hertzian dipole immersed in different media, including lossy dielectrics, media with negative permittivity and permeability, and zero-index media. © 2013 American Physical Society

Magnetic dipole super-resonances and their impact on mechanical forces at optical frequencies

Artificial magnetism enables various transformative optical phenomena, including negative refraction, Fano resonances, and unconventional nanoantennas, beamshapers, polarization transformers and perfect absorbers, and enriches the collection of electromagnetic field control mechanisms at optical frequencies. We demonstrate that it is possible to excite a magnetic dipole super-resonance at optical frequencies by coating a silicon nanoparticle with a shell impregnated with active material. The resulting response is several orders of magnitude stronger than that generated by bare silicon nanoparticles and is comparable to electric dipole super-resonances excited in spaser-based nanolasers. Furthermore, this configuration enables an exceptional control over the optical forces exerted on the nanoparticle. It expedites huge pushing or pulling actions, as well as a total suppression of the force in both far-field and near-field scenarios. These effects empower advanced paradigms in electromagnetic manipulation and microscopy. © 2014 Optical Society of America

Near-field electromagnetic trapping through curl-spin forces

Near-field electromagnetic trapping of particles is generally obtained by means of gradient forces. In this paper, we discuss the attractive behavior of curl-spin forces, as well as their potential for near-field electromagnetic trapping and manipulation. It is demonstrated that curl-spin forces enable the trapping of particles operating at their resonant frequency. Such phenomena can be exploited to design more efficient and selective electromagnetic traps, to boost near-field energy exchange systems, and to bring stability to coupled resonant radiators. It also is illustrated how the balance between the gradient, radiation pressure, and curl-spin force components leads to the formation of zero-force rings around their sources, which explicitly demarcate the trapping regions. Analytical and numerical analyses are presented to assess the stability of the trapping mechanism. © 2013 American Physical Society

Enhanced directed emission from metamaterial based radiation source

Cataloged from PDF version of article.The enhanced directed emission from a metasurface which is illuminated at its resonance frequency by a dipole source is experimentally demonstrated. The metasurface consists of two cutwire layers and a continuous wire layer in between, which exhibits strong magnetic dipole resonance under excitation normal to the plane. The scanned near-field patterns show the confinement of the field in the presence of metasurface, which, in turn, provides an enhanced and directional radiation in the far field. The far-field patterns are obtained by direct measurement and by a far-field transformation of the scanned near field, which are found to be in good agreement. (C) 2008 American Institute of Physics

EXPERIENCIAS DEMOSTRATIVAS SOBRE LA GESTIÓN SOSTENIBLE DEL USO DEL AGUA DE RIEGO, PARA REDUCIR EL GASTO ENERGÉTICO Y LAS EMISIONES DE GEI

[ES] La elección de un marco de riego y el estudio de materiales que permitan reducir las pérdidas de carga de una instalación, de manera que se consiga reducir la demanda de presión y por tanto la factura eléctrica con la misma efectividad de riego es clave, teniendo en cuenta que su vida útil es mayor de 20 años. Esto supondrá un ahorro continuado en el tiempo de explotación de la instalación. Además de este factor energético, es crucial determinar la Huella de Carbono de las intalaciones de riego, así como establecer la comparativa de la Huella de Carbono de los materiales utilizados en los dos marcos de riego (18 x 15T vs 12 x 15T) con sus diferentes variantes de instalación.Goñi Labat, M.; Puig Arrastia, J.; Ederra Gil, I. (2015). EXPERIENCIAS DEMOSTRATIVAS SOBRE LA GESTIÓN SOSTENIBLE DEL USO DEL AGUA DE RIEGO, PARA REDUCIR EL GASTO ENERGÉTICO Y LAS EMISIONES DE GEI. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1448OC

Near-field measurement of a planar meta-surface illuminated by dipole antennas

In this paper, the uniform illumination of a meta-surface that is fed by a single dipole antenna or an array is experimentally investigated by means of near-field measurements. The results of the scanned field, when the dipoles are radiating in free space and when the meta-surface is placed atop them are presented. By means of this measurement, the coupling reduction between dipoles of an array due to the presence of the meta-surface is observed. ©2008 IEEE