Symmetric Versus Asymmetric Coated (Half Coated) Fiber Optic SPR Sensor

Abstract

Fiber optic SPR sensors detect analytes without labels. These devices employ light-induced SPR. A symmetric fiber optic SPR sensor is made by coating one optical fiber with gold or silver and a dielectric material. Patterning the metal covering into a grating or nanostructure array generates surface plasmon waves. The fiber-linked light interacts with metal–dielectric contact surface plasmons. The sensor's surface plasmons’ resonant wavelength may be measured as it changes with the surrounding medium's RI to determine analyte concentration or binding events. Side-polished or tilted-fiber SPR sensors reveal the core of an asymmetric fiber optic SPR sensor by polishing one side of the cladding. The exposed core is coated in gold or silver. When light is angled toward the fiber, total internal reflection occurs. The core–analyte interface RI changes as the analyte binds to the metal-coated region, changing the angle of total internal reflection. Binding events and analyte concentrations can explain this change. Symmetric and asymmetric fiber optic SPR sensors are sensitive, adaptable, and real-time. A symmetric sensor may work for your application if the spatial placement is not critical. Asymmetric sensors, on the other hand, provide targeted fiber detection and additional sensor design flexibility. Symmetric and asymmetric fiber optic SPR sensors are sufficient for label-free sensing and detection in biological research, environmental monitoring, and chemical analysis. They are used in many fields because of their sensitivity and real-time readings.