Improving the near-field transmission efficiency of nano-optical transducers by tailoring the near-field sample

Despite research efforts to find a better nano-optical transducer for light localization and high transmission efficiency for existing and emerging plasmonic applications, there has not been much consideration on improving the near-field optical performance of the system by engineering the near-field sample. In this work, we demonstrate the impact of tailoring the near-field sample by studying an emerging plasmonic application, namely heat-assisted magnetic recording. Basic principles of Maxwell's and heat transfer equations are utilized to obtain a magnetic medium with superior optical and thermal performance compared to a conventional magnetic medium

Plasmon resonances of a prolate spheroid nanoparticle illuminated by a focused beam

The interaction of a radially focused beam with a prolate spheroidal nanoparticle is particularly important because it has the potential to produce strong nearfield electromagnetic radiation. Strong and tightly localized longitudinal components of a radially polarized focused beam can excite strong plasmon modes on elongated nanoparticles such as prolate spheroids. In this study, near field radiation from a prolate spheriodal nanoparticle is investigated when it is illuminated with a radially polarized focused beam of light. Nearfield radiation from the nanoparticle is investigated in the absence and presence of metallic layers

Polarization aspects of near-field radiation from nanoscale subwavelength apertures

It is demonstrated that a square nanoaperture can mediate polarized diffractionlimited radiation into nanoscale optical spots with the same polarization. A rectangular nanoaperture can convert linearly-polarized diffraction-limited radiation into circularly and elliptically-polarized nanoscale optical spots

Patterned medium for heat assisted magnetic recording

Heat assisted magnetic recording (HAMR) a potential solution to extend the limits of conventional magnetic recording. In HAMR, the heating of the recording medium is achieved with a near-field optical transducer. Although the literature suggests novel transducers, there is little consideration of the optical and thermal aspects of the magnetic medium. In this letter we suggest a recording medium that provides a significant enhancement in optical absorption and localized heating. The thermal profiles of the proposed medium and the conventional medium are compared using finite element method solutions of Maxwell’s and the heat transfer equations

Birefringent and dichroic behaviour of plasmonic nano-antennas

Birefringence and dichroism of plasmonic nano-antennas are investigated. We demonstrate that birefringent and dichroic behaviour of a cross-dipole nanoantenna is due to a length difference, and a relative plasmonic enhancement of the antenna particles, respectively

Av-avcı problemleri için kararlı sonlu eleman yöntemleri üzerine bir not

A numerical method that will improve and produce effective results for solving mathematical model for the system of predator-prey interactions which is defined by convection-diffusion-reaction problem is studied herein. We consider the Pseudo Residual-free Bubble (PRFB) method which is based on augmenting the finite element space by appropriate functions for the space discretization. The method is applied on different test problems and the numerical solutions are in good agreement with the result available in literature. The numerical results depict that the algorithm is efficient and feasible.Bu çalışmada, konveksiyon-difüzyon-reaksiyon problemleri ile modellenebilen av-avcı denklem sistemlerinin simülasyonunda kullanılan sayısal çözüm tekniklerini iyileştirecek ve daha etkin sonuçlar üretecek sayısal bir yöntem önerilmiştir. Uzay ayrıklaştırması için, sonlu elemanlar metodunu uygularken seçilen polinom baz fonksiyonlarına ilaveten fonksiyon uzayının özel tip fonksiyonlarla (residual-free bubbles) zenginleştirilmesine dayanan Pseudo Residual-free Bubble (PRFB) yöntemi kullanılmıştır. Söz konusu yöntem, çeşitli test örneklerine uygulanmış olup elde edilen sayısal çözümlerin, literatürde mevcut olan sonuçlar ile iyi bir uyum içinde olduğu gözlemlenmiştir. Sayısal sonuçlar, önerilen yöntemin verimli ve uygulanabilir olduğunu göstermektedir

Interaction of radially polarized focused light with a prolate spheroidal nanoparticle

The interaction of a nanoparticle with light is affected by nanoparticle geometry and composition, as well as by focused beam parameters, such as the polarization and numerical aperture of the beam. The interaction of a radially focused beam with a prolate spheroidal nanoparticle is particularly important because it has the potential to produce strong near-field electromagnetic radiation. Strong and tightly localized longitudinal components of a radially polarized focused beam can excite strong plasmon modes on elongated nanoparticles such as prolate spheroids. In this study, near field radiation from a prolate spheriodal nanoparticle is investigated when it is illuminated with a radially polarized focused beam of light. Near-field radiation from the nanoparticle is investigated in the absence and presence of metallic layers. It is shown that the interaction of a radially polarized focused beam with a prolate spheroidal nanoparticle can be enhanced by creating images of monopole charges using metallic layers. In addition, it is also observed that the presence of a metallic layer shifts the resonance of the prolate spheroid toward longer wavelengths. Dipole, quadruple, and off resonance field distributions for particles with different sizes and aspect ratios are presented when they are illuminated with a radially focused beam of light

Circularly polarized localized near-field radiation at the nanoscale

A novel nano-antenna configuration is suggested to achieve circularly polarized optical spots beyond the diffraction limit. Intense optical spots with circular polarization are obtained using a cross-dipole nano-antenna