The Localized Enhancement of Surface Plasmon Standing Waves Interacting With Single Nanoparticles

Real-time, high-sensitivity, and label-free detection to single nanoparticles has been achieved via visualizing the interaction between surface plasmon polaritons (SPPs) and nanoparticles, which is widely applied to chemistry and biology. In this work, aiming to enhance the detection sensitivity to nanoparticles, we explore the interaction of SPP standing waves with single nanoparticles. Compared with SPPs, the inhomogeneous fields of SPP standing waves modulate charge distributions around the particle and excite different electric dipole modes that tailor localized enhancements. For nanoparticles situating at electric antinodes of SPP standing waves, a vertical electric dipole is excited and high-density charges are stimulated around nanoparticle-film nanocavities, leading to further increased localized enhancement. The localized enhancement experiences more increase with smaller particle size, lower dielectric constant of surrounding medium, and lower particle refractive index. Via tailoring the localized enhancement by SPP standing waves, the sensitivity of SPP microscopy can be improved, which would broaden its applications on nanotechnology, biomedicine, and environmental monitoring.

Simulation of the Vertical-Vertical Controled Source Electromagtic Method

<div>Modeling of the Vertical-Vertical Controled Source Electromagtic Method (VVCSEM) on COMSOL Multiphysics. The VVCSEM method is, strictly speaking, an MCSEM (Marine Controlled Source ElectroMagnetic) that uses a vertical electric dipole as source, vertically oriented receivers, and time domain acquisition mode. Its main application is reservoir monitoring, reducing ambiguities encountered by conventional seismic and minimizing exploration risks in fields with complex geology. The present study shows the results of three-dimensional (3D) VVCSEM modeling built in COMSOL Multiphysics, aiming to analyze the electromagnetic field responses in different models and configurations. The VVCSEM proved to be efficient in detecting the proposed resistive anomalies, as expected and described in the literature.</div>

Simulation of the Vertical-Vertical Controled Source Electromagtic Method

<div>Modeling of the Vertical-Vertical Controled Source Electromagtic Method (VVCSEM) on COMSOL Multiphysics. The VVCSEM method is, strictly speaking, an MCSEM (Marine Controlled Source ElectroMagnetic) that uses a vertical electric dipole as source, vertically oriented receivers, and time domain acquisition mode. Its main application is reservoir monitoring, reducing ambiguities encountered by conventional seismic and minimizing exploration risks in fields with complex geology. The present study shows the results of three-dimensional (3D) VVCSEM modeling built in COMSOL Multiphysics, aiming to analyze the electromagnetic field responses in different models and configurations. The VVCSEM proved to be efficient in detecting the proposed resistive anomalies, as expected and described in the literature.</div>

Evaluation of the Trapped Surface Wave of a Vertical Electric Dipole Based on Undetermined Coefficient Method in the Presence of N-Layered Region: A Graphical Approach

In previous studies, the trapped surface wave, which is defined by the residue sums, has been addressed in the evaluation of the Sommerfeld integrals describing electromagnetic field of a vertical dipole in the presence of three-layered or four-layered region. But unfortunately, the existing computational scheme cannot provide analytical solution of the field in the presence of the N-layered region when N > 4. The scope of this paper is to overcome the limitations in root finding algorithm implied by the previous approach and provide solution of poles in stratified media. A set of pole equations following with explicit expressions are derived based on the undetermined coefficient method, which enable a graphical approach to obtain initial values of real roots. Accordingly, the generated trapped surface wave components are computed when both the observation point and the electric dipole source are on or near the surface of a dielectric-coated conductor. Validity, efficiency, and accuracy of the proposed method are illustrated by numerical examples.