Near-field simulation of obliquely deposited surface-enhanced Raman scattering substrates

Abstract

A semicontinuous gold layer on a template with a zigzag structure has been demonstrated to be a highly sensitive substrate for surface-enhanced Raman scattering (SERS). Obliquely deposited gold layers on different templates yield different SERS strengths. In this work, a finite-difference time-domain method is utilized to analyze the electric field distribution within the gold layer when the film is illuminated by light. The random gold nanostructures are scanned and transformed into binary images to allow them to be simulated. The field intensities and SERS enhancement factors of different samples are calculated and compared. Our analysis results reveal the near-field characteristics of strong SERS and agree closely with experimental measurements.

Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities

“…This technique would also be relevant for analytical purposes as, for example, the determination of the solution concentration of highly absorbent molecules following the position of the resonant peaks, an example of which is reported as Supporting Information in Figure S3. We envisage that, upon selection of the adequate dye molecule, other applications of this photonic detection could be found for the determination of pH and other liquid properties using dye indicators, , the formation of colored molecular complexes, molecular recognition, − or other sensing and biosensing applications where the decoupling between PS resonant features would be used as transduction principle.…”

Nanoporous Silver Films for Surface-Enhanced Raman Scattering-Based Sensing

“…, where N the total number of cells in the analysis area. 29 In this manner, electric field enhancement around each nanoscale feature (protrusion/ gap/ligament) and the electric field enhancement of the whole nanoporous Ag film were analyzed. Quantitative analyses demonstrate that protrusions, gaps, and ligaments contribute to the electric field enhancement of nanoporous Ag films.…”

Molecular Simulation Study of Surface-Enhanced Raman Scattering of Liquid Water

“…The metal particle in many cases is much larger than the target molecule and generates a frequency-dependent near-field due to the plasmon resonance with the incident/scattered fields. Among the established computational techniques, electrodynamic or electromagnetic methods are capable of describing the plasmonics, – where the metal is given as a frequency-dependent dielectric function in a continuum material model. One of the representative methods, the finite-difference time domain (FDTD), can simulate the field enhancement induced by the plasmon resonance in a macro-scale system, providing ancillary but helpful electromagnetic numerical analysis for the SERS. – This type has been developed to quantum hydrodynamics method based on Jellium model. – These are suitable for providing electrodynamics analyses in a macro-scale system but cannot give atomistic-level descriptions.…”