Liquid crystal filled dual-channel self-calibration optical-fiber surface plasmon resonance thermometer

In this paper, we propose and demonstrate a dual-channel self-calibration multimode optical-fiber surface plasmon resonance thermometer. The structure of this thermometer is mainly composed by dual sensing channels, in which one channel is coated with a gold layer surrounded by liquid crystal (LC), and the other is prepared with bilayers of silver and thin indium tin oxide (ITO) layer. The gold channel is the main channel, and the channel of the ITO layer with high refractive index is viewed as a configuration of self-calibration. The experimental results of the system show that the temperature sensitivities are 1.006 nm/°C in the range of 20°C-34°C and 0.058 nm/°C in the range of 35°C-80°C. In particular, at the phase transition temperature 34.5°C of changing from the nematic to the isotropic phase of the LC, the temperature sensitivity shows a step increase of 6.8 nm with a unit temperature change. This structure can be highly advantageous for temperature controlling and alarming in laboratory monitoring and industrial production.