Nanoresonator Integrated Fiber Optics Sensor for Pressure Immune Temperature Sensing Application

Resonant structures composed of metal nanoarray, insulator layer, and metal mirror (MIM) have been studied extensively due to their ultrasmall cavity volume and unique electric field distribution. Here, the nanoresonator comprised of gold film, poly(methylmethacrylate) (PMMA) layer, and gold grating has been experimentally fabricated on fiber tip and demonstrated its application in pressure immune temperature sensing. Numerical simulation results indicate that the temperature sensing performance of the first-order nanoresonance mode is better than Fabry–Perot interference modes, contributed by the synergetic effect of thermo-optic effect and thermal expansion effect of the intermediate polymer layer. The fiber optics sensor is realized by a wet transfer technology, through transferring a composite layer of gold and PMMA on a fiber tip with gold grating to obtain the compact sandwich structure. A temperature sensitivity of −148.42 pm/°C has been achieved in the temperature range of 20 °C and 100 °C. More importantly, the compact optical sensor can be immune from external pressure, which effectively reduces the interference from external pressure during its sensing on temperature.