A novel plasmonic sensor based on light-diffusing fibers with built-in measuring cell

In this work, a novel Surface Plasmon Resonance (SPR) sensor based on plastic light-diffusing fibers (LDFs) has been developed and investigated. The plasmonic platform structure includes an integrated measuring cell to avoid complex microfluidic systems and all the downsides that characterize them. In a first step, the developed sensor configuration has been optically tested in a refractive index range between 1.332 and 1.371 and then compared with other configurations. The obtained results have highlighted an improvement of about 40% in terms of bulk sensitivity with respect to a similar experimental configuration based on the same LDF but without modification, despite a slight worsening in terms of Full Width at Half Maximum (FWHM), whose value increases of about 20%. So, the obtained experimental results have denoted the possibility and feasibility of using this plasmonic configuration in biochemical sensing application fields. In particular, the proposed SPR sensor platform offers two key characteristics: a convenient measuring cell into the optical fiber and better sensitivity in the considered refractive index range. Furthermore, the plasmonic sensing region in the measuring cell can be combined with simple microfluidic systems or a dropping approach.