Abstract (EN):
This paper explores and compares three different plasmonic optical fibre sensor configurations, based on D-type and suspended core fibres combined with metallic nanowires, and investigates how their different geometrical parameters can affect the coupling between the guided optical mode supported by fibres and the localized plasmonic modes, and how that ultimately results in improved sensor performance. Fibre optical sensors based on plasmonic resonances with metallic nanostructures have revolutionized the field of optical sensing because they have permitted to obtain sharper and fine-tuned resonances with higher sensitivity. The essence for exploring the properties of localized plasmonic modes and their coupling with the optical guided mode depends not only on the choice of the materials employed in the device, but also on the geometry of the different components and their relative position, which ultimately determines the spatial distributions of optical power of the different modes and consequently their overlap and coupling. In this work, we use numerical simulations based on finite element methods to demonstrate the importance of shaping the features of the guided optical mode to promote the coupling with the localized modes, in the two types of fibres considered. The results clarify some of the fundamental aspects behind the operation of these devices and provide novel proposals for enhanced refractive index sensors.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
6