Surface Plasmon Resonance sensors based on polymer optical fiber

Surface Plasmon Resonance (SPR) is a powerful technique for directly sensing in biological studies, chemical detection and environmental pollution monitoring. In this paper, we present polymer optical fiber application in SPR sensors, including wavelength interrogation SPR sensor and surface enhanced Raman scattering (SERS) probe. Polymer optical fiber (POF) is used to effectively couple the incident light from light source, and collect reflective light into spectrometer. It also makes the sensing system more flexible and reliable. Gold nanorods with 30 nm long axis and average aspect ratios 3:1 are synthesized using seed-mediated growth method. Combining Au nanorods with POF, we can easily realize fiber SERS sensor. Long-period fiber gratings are fabricated on single mode polymer optical fiber with 120 um period and 50% duty cycle. The polarization characteristic of this kind of birefringent grating is studied. Theoretical analysis shows this type grating has two separated polarization peaks, and it will be advantageous in SPR sensing applications.