Análise de biossensores ópticos baseados no efeito SPR utilizando novos modelos de dispositivos quase cristalinos

Abstract

With the continuous advancement of new communications technologies across all scientific fields, it is essential that the devices employed keep pace with these developments to ensure reliable results. In this context, applications at very high frequencies have been explored to develop devices with ultra-fast responses. Among these applications, optical sensors have been the subject of extensive research. This work utilizes the Surface Plasmon Resonance (SPR) effect for the analysis of optical sensors based on different models of optical waveguides. The SPR effect occurs when a metaldielectric interface is excited by a light signal at a specific frequency, known as the surface plasmonic frequency, inducing the formation of dense electron clusters in the analysis region, thereby enabling material detection. The objective of this study is to propose and analyze four novel models of plasmonic sensors derived from optical waveguides, including microstructured optical fibers and conventional waveguides. In the first approach, a microstructured optical fiber with elliptical holes was used, exploring two variations: one with an extended core and another with dual cores. The second study involves a microstructured D-type optical fiber, where a defect in the silica (𝑆𝑖𝑂2 ) core was doped with varying concentrations of germanium dioxide (𝐺𝑒𝑂2 ) to optimize the SPR effect. The third proposed structure consists of a rib-type optical waveguide with a microchannel coupled, separated from the guiding region by a thin layer of gold. Lastly, the final proposed structure employs a quasi-periodic microstructured optical fiber, introducing liquid crystal sensitive to temperature variations to enhance the coupling between the fundamental and plasmonic modes. To evaluate the effectiveness of the sensors, the electric (E) and magnetic (H) field distributions, confinement loss (CL) and wavelength sensitivity (WS) were studied. These investigations aim to contribute to the development of advanced optical sensors capable of accurately detecting variations in the refractive index of materials in both chemical and biological applications.