Long-Range Surface Plasmon Resonance Sensor Based on Side-Polished Fiber for Biosensing Applications

A long-range surface plasmon resonance (LRSPR) sensor with enhanced performance has been theoretically calculated and experimentally investigated for biosensing applications. The LRSPR-based sensor is fabricated by employing a side-polished multimode fiber as a waveguide and MgF
₂
as a buffer layer beneath a thin silver film for supporting LRSPR excitation. Theoretical optimization based on transfer matrix method and the corresponding validation experiments were carried out in detail. The theoretical and experimental results consistently indicate that the sensing performance parameters of the LRSPR-based sensor are improved with varying degrees in comparison to conventional SPR (CSPR) sensors. It was experimentally achieved that the maximal figure of merit of the LRSPR-based sensor exceeds that of the CSPR sensor by a factor of 1.14. At last the bovine serum albumin (BSA) concentration detection was performed to further confirm the sensitivity enhancement of the optimized sensor in biosensing. This SPR sensor design and development is expected to exert a positive influence on real-time and label-free.