Fabrication and Operation Analysis of a Surface-Plasmon Sensor Using a Nonpropagating Mode

Abstract

Our research focuses on the development of a surface-plasmon sensor that uses a stationary surface plasmon, referred to as a "non-propagating mode." This mode is observed when light is incident perpendicularly on a surface-plasmon sensor based on a metal diffraction grating. We performed a comprehensive analysis of the behavior of the surface-plasmon resonances within this non-propagating mode, employing the rigorous coupled-wave analysis (RCWA) method. Using electron-beam lithography, sputtering, and a lift-off process, we fabricated such a surface-plasmon sensor and evaluated its optical properties rigorously. By combining simulations and experiments, we successfully utilized the nonpropagating mode to detect a liquid medium with a refractive index of 1.70. Simulations show that the non-propagating mode arises due to a Fano resonance; i.e., to a resonant interaction between a localized surface plasmon generated at the edge of a metal grating strip during normal incidence and a propagating surface plasmon that occurs at the boundary between the metal diffraction grating and the measurement medium. The present results provide useful information for the advancement of surfaceplasmon sensing technologies.

TM- and TE-polarization-selective narrowband perfect absorber for near-ultraviolet light using Fano resonance in an aluminum nanohole array structure

“…This electric dipole then couples to a propagating surface plasmon (PSP) via an electric eld along the z-axis. The coupling of these two surface plasmons is thought to induce the Fano resonance [37], causing strong absorption. To con rm the Fano resonance, the spectrum of the absorbance wavelength shown in Fig.…”