RESUMO
Using a finite-element, full-wave modeling approach, we present a flexible method of analyzing and simulating dielectric and plasmonic waveguide structures as well as their mode coupling. This method is applied to an integrated plasmonic circuit where a straight dielectric waveguide couples through a straight hybrid long-range plasmon waveguide to a uniformly bent hybrid one. The hybrid waveguide comprises a thin metal core embedded in a two-dimensional dielectric waveguide. The performance of such plasmonic circuits in terms of insertion losses is discussed.
Assuntos
Teoria dos Jogos , Luz , Dispositivos Ópticos , Refratometria/métodos , Espalhamento de Radiação , Ressonância de Plasmônio de Superfície/métodos , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Metais/químicaRESUMO
The diffusion of charged proteins in liquid-filled nanometer-sized apertures with charged surfaces has been investigated with fluorescence correlation spectroscopy (FCS). Based on a two-dimensional (2D) multicomponent diffusion model, key parameters such as the number of molecules diffusing freely inside the nanochannel or interacting with the surfaces, together with the specific diffusion parameters, could be extracted. Different regimes of diffusion have been observed and described by a model, which takes into account the steric exclusion, the reversible surface adsorption of the biomolecules, and the exclusion-enrichment effect that is due to the charge of the proteins and the ionic strength of the solution. Conditions where the diffusion of proteins through nanoconfined spaces can be of the same magnitude as in the bulk were both predicted and experimentally verified.
Assuntos
Corantes Fluorescentes/química , Nanoestruturas/química , Espectrometria de Fluorescência/métodos , Aglutininas do Germe de Trigo/análise , Algoritmos , Difusão , Espectrometria de Fluorescência/instrumentação , Propriedades de Superfície , Aglutininas do Germe de Trigo/químicaAssuntos
Adenina/análogos & derivados , Carbocianinas/química , Corantes Fluorescentes/química , Processamento de Imagem Assistida por Computador , Microscopia de Fluorescência , Adenina/química , Linhagem Celular Tumoral , Guanina/química , Humanos , Microtúbulos/ultraestrutura , Nanoestruturas/química , Tubulina (Proteína)/químicaRESUMO
A straightforward method to achieve super-resolution consists of taking an image sequence of stochastically blinking emitters using a standard wide-field fluorescence microscope. Densely packed single molecules can be distinguished sequentially in time using high-precision localization algorithms (e.g., PALM and STORM) or by analyzing the statistics of the temporal fluctuations (SOFI). In a face-to-face comparison of the two post-processing algorithms, we show that localization-based super-resolution can deliver higher resolution enhancements but imposes significant constraints on the blinking behavior of the probes, which limits its applicability for live-cell imaging. SOFI, on the other hand, works more consistently over different photo-switching kinetics and also delivers information about the specific blinking statistics. Its suitability for low SNR acquisition reveals SOFI's potential as a high-speed super-resolution imaging technique.
RESUMO
We perform rigorous simulations of hybrid long-range modes guided by a central metal core and a two-dimensional dielectric slab. We show that these modes are subject to fewer limitations than conventional long-range plasmon modes in terms of field confinement and guiding performance. These hybrid modes may offer substantial improvements for integrated plasmonic components, as illustrated here by the consideration of 90 degrees bends.