Tuning dynamic range and sensitivity of white-light, multimode, fiber-optic surface plasmon resonance sensors

This paper presents the advantages of modifying the geometry of the sensing tip of a white-light, multimode optical fiber SPR sensor to optimize the dynamic range and sensitivity. By selectively beveling the distal end of the fiber probe, the wavelength of resonance can be redshifted by more than 100 nm and blue-shifted by more than 30 nm, This increases the flexibility of a white-light SPR sensor by increasing the dynamic range of accessible RIs and by shifting the resonance to the most sensitive regions of the detector. Sensitivity, measured in wavelength shift per RI change, can be increased by a factor of 4, Also, multiple-wavelength regions of SPR activity can simultaneously be observed on the same probe, thus increasing the information content of a SPR spectrum.