Analyte detection based on SPR in 12-fold quasi-periodic PCF

Abstract

In this article, an SPR sensor based on 12-fold quasi-periodic PCF composed of Ge-doped silica is introduced for analyte detection. The outer surface of the cladding is covered by a 40 nm gold layer serving as the plasmonic layer for the proposed sensor. The birefringence induced due to the inherent characteristic of the 12-fold pattern in the cross-section provides discrepancy for the operation of the structure regarding x- and y-polarizations. The wavelength sensitivity, amplitude sensitivity, and resolution of 12150 nm.RIU−1, 678 RIU−1, and 8.23 × 10–6 RIU, respectively are obtained for the proposed sensor. The FEM method has been implemented to investigate the performance of the proposed sensor for biosensing application in a detection range of 1.33–1.41.

Orthogonal-Sided Polished Microstructured Optical Fiber-Based SPR Sensor for Simultaneous Measurement of Temperature and Refractive Index

“…thus leading to the movement of a resonance peak toward longer wavelengths [12]- [16], [25], [26]. Another consequence of the larger d c is expulsion of the modal field from the centre of the core area to the metallic interface, as seen from insets A-C in the Figs.…”

“…The polished planes of the two MOFs can be easy coated with the gold layer uniformly. Moreover, to lower the RI of the core mode to facilitate the phase matching problem [12]- [16], [25], [26], we also introduce a small air hole into the core center of the two fiber. In order to investigate and contrast their sensing performance, the two sensors have the same structure parameters.…”

“…In these two sensors, an air hole is introduced into the fiber core to lower the effective RI (n eff ) of a core mode, which is a common way to facilitate the phase matching and improve the sensing performance [12]- [16], [25], [26]. Figs.…”

“…For the temperature sensing, the temperature coefficient appears a little irregular behavior as d c changing, because it is effected by many complicated factors, such as thermal expansion effect, phonon-electron and electron-electron scatterings. While for the RI sensing, RI coefficient shows a growing tendency with the d c increasing, because the larger d c can lower the n eff of a core mode, hence facilitating the phase matching between the core modes and the SPP modes, and resulting in a higher RI sensitivity [12]- [16], [25], [26].…”

“…R ECENTLY, microstructured optical fiber (MOF) based surface plasmon resonance (SPR) sensors have attracted more attention because of their advantages of flexible structure design and adjustable optical properties [1]- [12]. Compared with the traditional fiber based SPR sensors, one of the main advantages of the MOF-based SPR sensors is that it can boost the phase matching problems, and thus effectively tuning the resonance wavelength and improving the sensing performance [12]- [16]. In the early development of the MOF-based SPR sensors, to implement SPR sensing for liquid samples, the holes of the MOFs need to be coated with the metal films or placed with wires, and then filled with the samples [10], [13]- [18].…”