Far‐ and Deep‐Ultraviolet Surface Plasmon Resonance Sensor

Plasmonics in the UV region has been widely focused because of the higher energy and the abundant electronic resonances compared to the conventional visible plasmonics. Recently, we have investigated the surface plasmon resonance (SPR) properties of the Al film, aiming for the application as refractive index sensors. Utilizing the UV lights, we expect three advantages: high sensitivity, material selectivity, and surface selectivity. By using an original attenuated total reflectance spectroscopic instrument, Al‐SPR angle and wavelength were investigated with changing environments on the Al film. Al film thickness and materials of prisms on which Al was evaporated were also important factors for the SPR properties. By optimizing the conditions, the Al film worked as a sensor both in air and in liquids. In addition, our established system expands the plasmonics into an even higher energy region than 200 nm, while the UV‐plasmonics have been studied in the wavelength region longer than 200 nm. Recently, UV‐plasmonics have received much attention because of the high energy and abundant electronic resonances in comparison with the conventional visible‐plasmonics. In this personal account, our recent investigations about the surface plasmon resonance (SPR) properties of Al films are summarized. Utilizing the UV light, we expect three advantages as refractive index sensors: high sensitivity, material selectivity, and surface selectivity. Our original attenuated total reflectance spectroscopic system enables us to measure the SPR properties in the UV region: down to 170 nm.