Abstract
In this paper, we demonstrate a long-range surface plasmon resonance (LRSPR) sensor based on D-shaped hexagonal structure photonic crystal fiber (PCF) with buffer layer of magnesium fluoride (MgF2). The theoretical analysis is first introduced to reveal surface plasmon polariton (SPP) mode excitation by the y-polarized core-guided mode. The influences exerted by different thicknesses of Au film and MgF2 buffer layer are theoretically investigated with the full vectorial finite element method for optimizing structure parameters. A novel status of electric field boundary (SEFB) technique is proposed to analyze the reciprocal sensing performance of symmetric LRSPR (sLRSPR) sensor. Theoretical simulation reveals that the LRSPR with PCF/MgF2 (100 nm)/Au (50 nm) architecture exhibits the significant performance and has an intensity sensitivity improvement of 160.13% compared with conventional SPR (cSPR) sensor. With the simulation providing the theoretical basis, a proof-of-concept experiment is performed with the D-shaped PCF fabricated by a wheel polishing system. The experimental results show good agreement with the theoretical calculations, and both of them consistently indicate that the LRSPR-based sensor has an improved intensity sensitivity (−490.625% RIU−1) and an increased penetration depth. Furthermore, focusing on the sensing principle, the proposed SEFB method can be applied in the analysis of other types of multilayer SPR sensor. The optimal LRSPR sensor with improved detection accuracy shows great promise for applications in the field of biochemical measurement.
Published Version
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