Extended discrete dipole approximation and its application to bianisotropic media

In this research we introduce the formalism of the extension of the discrete dipole approximation to a more general range of tensorial relative permittivity and permeability. Its performance is tested in the domain of applicability of other methods for the case of composite materials (nanoshells). Then, some early results on bianisotropic nanoparticles are presented, to show the potential of the Extended Discrete Dipole Approximation (E-DDA) as a new tool for calculating the interaction of light with bianisotropic scatterers

Pembuatan Peta Zona Nilai Ekonomi Kawasan (Znek) Menggunakan Tcm (Travel Cost Method) Dan Cvm (Contingent Valuation Method) Berbasis Sistem Informasi Geografis (Studi Kasus : Candi Prambanan)

Prambanan Temple has potential as a tourist attraction. The strategic location which have historical value, makes this Place became one tourist destination areas Klaten. Based on this, we need a Zone Map Economic Value Areas (ZNEK) to the Prambanan area of the palace to estimate the economic value and benefits based on willingness to pay (WTP) tourists and the people who benefit from the region. Sampling method (respondents) were used in this research is non probability sampling with accidental sampling technique, where respondents are those who by chance / accidental encountered in the study area and can be used as a sample, if it is considered that the person who happened to be found suitable as a data source. Data processing method used is multiple linear regression analysis and calculation software WTP using Maple 17.Results obtained from the study of this final project is the Economic Value Area Zone maps with the total value of economic attraction Prambanan Temple Rp.32.851.020.029.000,- Maps generated from the integration of economic and spatial aspects can be used as an objective consideration of the decision-making process in the spatial field and economic field for the government to optimize and simplify the process of the asset\u27s management and monitoring the natural resources potential. Besides being able to provide a solution for the management of resource constraints of the economy in various regions in Indonesia, the map can be used too as a learning tool for the public society to bring awareness of the importance of potential belonging

Nanoscopic surface inspection by analyzing the linear polarization degree of the scattered light

We present an optical method for the nanoscopic inspection of surfaces. The method is based on the spectral and polarization analysis of the light scattered by a probe nanoparticle close to the inspected surface. We explore the sensitivity to changes either in the probe–surface distance or in the refractive index of the surface

Impact of the interfacial thermal conductance on the thermoplasmonic response of metal/polymer hybrid nanoparticles under nanosecond pulsed illumination

Janus nanoparticles containing plasmonic materials have attracted great attention in the thermoplasmonic community due to their potential for applications in thermoelectronics or biomedicine. A significant number of thermoplasmonic applications rely on the heating of nanostructures by using pulsed excitation lasers. The heating generated in these nanostructures is often transferred to other regions via material–fluid interfaces. This heat transfer dynamics is controlled by the interfacial thermal conductance. In this work, we investigate the impact of the interfacial thermal conductance on the thermal relaxation of metal–polymer Janus nanoparticles that generate directional heating under pulsed illumination. We show that neglecting the temperature dependence of the thermophysical properties results in an overestimation of the temperature of the nanoparticle. A gold/polymer semishell nanostructure was used as an example not only to illustrate the aforementioned effects but also to show it as a reliable nanoheater candidate for photothermal therapies, capable of offering a remarkable temperature increment and presenting directional heating. The model we developed here can be applied to any type of nanoarquitecture, showing this work as a powerful tool for topics beyond photothermal therapies that can contribute to the development of novel structures able to control heat on the nanoscale

Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion

Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field 'hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments

Plasmonic nickel nanoantennas

7 páginas, 6 figuras.-- El pdf del artículo es la versión post-print.-- et al.The fundamental optical properties of pure nickel nanostructures are studied by far-field extinction spectroscopy and optical near-field microscopy, providing direct experimental evidence of the existence of particle plasmon resonances predicted by theory. Experimental and calculated near-field maps allow for unambiguous identification of dipolar plasmon modes. By comparing calculated near-field and far-field spectra, dramatic shifts are found between the near-field and far-field plasmon resonances, which are much stronger than in gold nanoantennas. Based on a simple damped harmonic oscillator model to describe plasmonic resonances, it is possible to explain these shifts as due to plasmon damping.Supported by the European FP7 project ‘Nanoantenna’ (FP7-HEALTH-F5-2009-241818-NANOANTENNA) and the National Project MAT2009 –08398 from the Spanish Ministerio de Ciencia e Innovacion. J.A. acknowledges fi nancial help by the Department of Industry of the Basque Government through the ETORTEK program NANOPHOT. P.V. acknowledges funding from the Basque Government under Programs No. PI2009–17 as well as the Spanish Ministry of Science and Education under Project No. MAT2009–07980. Z. P. acknowledges support from Swedish Foundation for Strategic Research through RMA08–0109 “Functional Electromagnetic Metamaterials” program. J. N. acknowledges funding from the Generalitat de Catalunya and the Spanish Ministry of Science and Education through No. 2009-SGR-1292 and No. MAT2010–20616-C02 projects. A.D. acknowledges support from the Swedish Research Council.Peer reviewe

Thermophoresis and thermal orientation of Janus nanoparticles in thermal fields

Thermal fields provide a route to control the motion of nanoparticles and molecules and potentially modify the behaviour of soft matter systems. Janus nanoparticles have emerged as versatile building blocks for the self-assembly of materials with novel properties. Here we investigate using non-equilibrium molecular dynamics simulations the behaviour of coarse-grained models of Janus nanoparticles under thermal fields. We examine the role of the heterogeneous structure of the particle on the Soret coefficient and thermal orientation by studying particles with different internal structures, mass distribution, and particle–solvent interactions. We also examine the thermophoretic response with temperature, targeting liquid and supercritical states and near-critical conditions. We find evidence for a significant enhancement of the Soret coefficient near the critical point, leading to the complete alignment of a Janus particle in the thermal field. This behaviour can be modelled and rationalized using a theory that describes the thermal orientation with the nanoparticle Soret coefficient, the mass and interaction anisotropy of the Janus nanoparticle, and the thermal field’s strength. Our simulations show that the mass anisotropy plays a crucial role in driving the thermal orientation of the Janus nanoparticles

Janus-Nanojet as an efficient asymmetric photothermal source

The combination of materials with radically different physical properties in the same nanostructure gives rise to the so-called Janus effects, allowing phenomena of a contrasting nature to occur in the same architecture. Interesting advantages can be taken from a thermal Janus effect for photoinduced hyperthermia cancer therapies. Such therapies have limitations associated to the heating control in terms of temperature stability and energy management. Single-material plasmonic nanoheaters have been widely used for cancer therapies, however, they are highly homogeneous sources that heat the surrounding biological medium isotropically, thus equally affecting cancerous and healthy cells. Here, we propose a prototype of a Janus-Nanojet heating unit based on toroidal shaped plasmonic nanoparticles able to efficiently generate and release local heat directionally under typical unpolarized illumination. Based on thermoplasmonic numerical calculations, we demonstrate that these Janus-based nanoheaters possess superior photothermal conversion features (up to ΔT≈35 K) and unique directional heating capacity, being able to channel up over 90% of the total thermal energy onto a target. We discuss the relevance of these innovative nanoheaters in thermoplasmonics, and hyperthermia cancer therapies, which motivate the development of fabrication techniques for nanomaterials

Plasmonic linear nanomotor using lateral optical forces

Optical force is a powerful tool to actuate micromachines. Conventional approaches often require focusing and steering an incident laser beam, resulting in a bottleneck for the integration of the optically actuated machines. Here, we propose a linear nanomotor based on a plasmonic particle that generates, even when illuminated with a plane wave, a lateral optical force due to its directional side scattering. This force direction is determined by the orientation of the nanoparticle rather than a field gradient or propagation direction of the incident light. We demonstrate the arrangements of the particles allow controlling the lateral force distributions with the resolution beyond the diffraction limit, which can produce movements, as designed, of microobjects in which they are embedded without shaping and steering the laser beam. Our nanomotor to engineer the experienced force can open the door to a new class of micro/nanomechanical devices that can be entirely operated by light

Plasmonic Control of Radiative Properties of Semiconductor Quantum Dots Coupled to Plasmonic Ring Cavities

In recent years, a lot of effort has been made to achieve controlled delivery of target particles to the hotspots of plasmonic nanoantennas, in order to probe and/or exploit the extremely large field enhancements produced by such structures. While in many cases such high fields are advantageous, there are instances where they should be avoided. In this work, we consider the implications of using the standard nanoantenna geometries when colloidal quantum dots are employed as target entities. We show that in this case, and for various reasons, dimer antennas are not the optimum choice. Plasmonic ring cavities are a better option despite low field enhancements, as they allow collective coupling of many quantum dots in a reproducible and predictable manner. In cases where larger field enhancements are required, or for larger quantum dots, nonconcentric ring-disk cavities can be employed instead