Optical Fiber Sensing Technologies

7Surface Plasmon Resonance‐Based Optical Fiber Sensing Technology

Surface plasmons (SPs) are collective oscillations of the free electron gas in metals that exist at the interface between two materials with dielectric constants of opposite signs, such as a metal and a dielectric. When the propagation constant of the excitation photons matches that of the electron oscillations, surface plasmon resonance (SPR) occurs, where part of the energy of the incident light is transferred to the SPs. The resonant condition depends on the dielectric constants of the metal and dielectric that support the interface. When the dielectric around the metal changes, the SPR resonant condition changes accordingly. SPR is an effective sensing technology and has ...