Aluminum-Based Deep-Ultraviolet Surface Plasmon Resonance Sensor

An aluminum-based deep-ultraviolet surface plasmon resonance (DUV-SPR) sensor is promising for biological applications. Design aspects of a DUV-SPR sensor are here considered by using Fresnel multilayer model. Angular and wavelength interrogation modes are used, where fused silica, sapphire, and acrylic solacryl ultraviolet transmittance (acrylic SUVT) are used as optical substrates. Aluminum at its oxidized state (alumina) is also considered as an aluminum overlayer. Our 4-layer Kretschmann-Raether-based SPR sensor is applied for gaseous and aqueous solutions, where some figures of merit are used to analyze the sensor performance. Values for sensitivity, linewidth (FWHM, full width at half maximum), and FOM (figure of merit or quality factor) are calculated. Resolution is also found and compared with other devices by using a known formulation. The results indicate that our sensor has a higher sensitivity for both gaseous and aqueous solutions when compared with the visible light-based sensor. For aqueous solutions, analyte is simulated as a bulk or a monolayer. Therefore, DUV-SPR sensors are a good alternative to the conventional visible-based SPR devices, where the performance is similar or higher for some conditions, having a higher affinity for some proteins.