Designing highly sensitive exposed core surface plasmon resonance biosensors

Abstract

With technological advancement, photonic crystal fibers (PCFs) are effectively used to design miniaturized, flexible, and efficient biosensors. This paper proposes an exposed core PCF biosensor based on widely known surface plasmon resonance (SPR) phenomena. An external sensing mechanism is followed to characterize the sensing performance within the refractive index (RI) range between 1.28 and 1.40. Metal strip (gold (Au) and titanium dioxide (TiO 2 )) is deposited on the outer surface only along the four channels instead of the entire surface, which could decrease the difficulties associated with the metal deposition on the entire circular surface. Simulating the sensor using finite element method based COMSOL Multiphysics software, we find tremendous amplitude sensitivity of 7420.69 RIU −1 and wavelength sensitivity of 87,000 nm/RIU. In addition, the sensor offers the highest resolution of 7.7×10 −6 RIU, the figure of merit of 1011.63 RIU −1 , signal to noise ratio of 10.05 dB, the detection accuracy of 0.016598 nm −1 , and detection limit of 102.23 nm. However, the promising sensing performance indicates that the proposed sensor could be implemented effectively to detect different biological and chemical substances.