The Temperature Responsive Mechanism of Fiber Surface Plasmon Resonance Sensor

Abstract The temperature responsive mechanism of the optical fiber Surface Plasmon Resonance (SPR) sensor is analyzed. It is found that, both the gold film and the fiber core change with increasing temperature and affect the temperature sensitivity of the SPR sensor, but the main factor of the intrinsic temperature sensitivity of the sensor is the temperature dependent SPR response of the gold coating. The gold film plasma frequency plays a critical role in the temperature response mechanism of the sensor. Experimental and simulation results show that the SPR wavelength shift due to the change of the gold film temperature contributes 19.6% to the total, as the sensor surrounded with ethanol and the environment temperature increases from 0℃ to 50℃. The reason is that the plasma frequency of the gold film rises significantly as the external temperature increases. The rising rate of plasma frequency with temperature is related to the morphology and the deposition method of the gold film. This result has provided a novel insight on the physical properties of optical fiber SPR sensors and has improved the capability of SPR sensors for measuring signals in a temperature-changing environment.