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) and relative humidity (RH), usually affect the performances of common temperature sensors or hinder signal demodulation. 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 an optical adhesive. No extra processing is required for the fiber platform, guaranteeing fabrication efficiency and device strength. Because of the thermal expansion and contraction, the effective RI of the adhesive varies, resulting in the resonance wavelength of the nanohole array/adhesive interface being sensitive to external temperature change. A linear response with a high-temperature sensitivity of 142.5 pm/°C is realized in the range from 20 °C to 60 °C; moreover, a response time of 2.11 min and a recovery time of 4.09 min are obtained. The plasmonic fiber probe possesses excellent selectivity, compactness, and easy fabrication, which will release its potential in versatile application scenes where temperature selectivity is preferred. Benefiting from the tunability of the nanohole array, the performance of the fiber probe can, moreover, be optimized on demand, e.g., operation wavelength, bandwidth, sensitivity, etc.