A Compact and Selective Plasmonic Fiber Probe for Temperature Detection.

Temperature detection is of significance in environmental control, health care and biomedical engineering. However, surrounding conditions, e.g., refractive index (RI), relative humidity (RH), usually affect the performances of common temperature sensors or hinder the signal demodulations. Here, we propose a compact plasmonic fiber probe for selective temperature detection. This fiber probe is fabricated through integrating a metal-deposited nanohole array template onto a multimode fiber tip facet using optical adhesive. No extra processing is required for the fiber platform, guaranteeing the fabrication efficiency and device strength. Due to the thermal expansion and contraction, the effective RI of the adhesive varies, resulting in that the resonance wavelength of the nanohole array/adhesive interface is sensitive to external temperature change. A linear response with a high temperature sensitivity of 142.5 pm/°C is realized in the range of 20 to 60 °C. Moreover, a response time of 2.11 minutes and a recovery time of 4.09 minutes are obtained. The plasmonic fiber probe possesses an excellent selectivity, compactness, easy-fabrication, which will release its potential in versatile application scenes where a temperature selectivity is preferred. Moreover, benefiting from the tunability of nanohole array, the performance of the fiber probe can be optimized on demand, e.g., operation wavelength, bandwidth, sensitivity, etc.