Surface Plasmon Resonance Sensors in Far- and Deep-Ultraviolet Regions

Abstract

Surface plasmon resonance (SPR) in the ultraviolet region attracts much attention due to the higher energy and abundant molecular electronic transitions therein compared to those in the visible region. Herein, we investigated the SPR of aluminum (Al) thin films with varying refractive index of the environment near the films in the far‒ultraviolet (FUV, ≤ 200 nm) and deep‒ultraviolet (DUV, ≤ 300 nm) regions. By using our original FUV‒DUV spectrometer which adopts an attenuated total reflectance (ATR) system, the measurable wavelength range was down to the 180 nm, and the environment near the Al surface could be controlled. Based on the obtained spectra, the dispersion relation of Al‒SPR in the FUV and DUV regions was obtained. The FUV‒DUV‒SPR sensors are expected to have three advantages compared to visible-SPR sensors: higher sensitivity, material selectivity, and surface specificity.