基于塔姆等离激元的双参数测量光纤探针传感器 (特邀)

Objective To address the technical challenges of traditional fiber-optic sensors in multi-parameter measurements, such as temperature-refractive index cross-sensitivities, complex structures, and low sensor strengthen, this study proposes a design scheme of optical fiber tip sensor based on Tamm Plasmon Polaritons (TPP). It aims to develop a high-sensitivity dual-parameter sensor for independent, accurate measurements of refractive index and temperature, with simplified fabrication and enhanced stability. It provides a novel technical reference for multi-parameter detections in biochemical and environmental monitoring. Methods This study combined numerical simulation and experimental measurements. The sensor was obtained by functionalizing the fiber endface with a distributed Bragg reflector (DBR) of 6 pairs of alternating SiO₂/Ta₂O₅ layers and a gold nanomembrane with hexagonal array of nanoholes. The two-dimensional Finite-Difference Time-Domain (FDTD) method was used for electromagnetic simulation to characterize the electric field distributions of the two resonant modes. A copper sacrificial layer and a gold film were deposited on an as fabricated silicon template sequentially, which was then immersed in a copper etchant. The copper sacrificial layer was dissolved to release the gold nanomembrane, and the gold nanomembrane was transferred onto the fiber endface with DBR coated to obtained the fiber tip sensor. Refractive index experiments were conducted with solutions of different refractive indices as the analytes, and temperature sensing experiments were carried out using a temperature control box. The changes in the reflection spectrum of the sensor were measured to analyze the wavelength shift of the resonant modes. Results and Discussions In the refractive index range of 1.3330-1.3684, Mode 1 (TPP) had no obvious wavelength shift, while Mode 2 (LSP) showed a regular red shift with a total shift of 12.3 nm and a sensitivity of 361.25 nm/RIU was obtained with a good linear relationship. In the temperature test of 20-60 ℃, both modes blue-shifted with temperature increasing. The temperature sensitivities were 0.072 nm/K and 0.0778 nm/K, respectively. The wavelengths recovered during cooling, indicating a good dynamic response and repeatability of the fiber sensor. Based on the differentiated characteristics that Mode 1 is only temperature-sensitive and Mode 2 is sensitive to both refractive index and temperature, a cross-sensitivity matrix and a decoupling model were constructed to realize high-precision measurement of the two parameters, effectively solving the cross-sensitivity problem. Conclusions A fiber tip sensor for the dual-parameter measurement of refractive index and temperature based on Tamm plasmon polariton functional units is proposed and demonstrated in this paper. Experimental results show that the fiber tip sensor can effectively excite two resonant modes by introducing periodic micro-nano structures into the gold nanomembrane, and the two modes exhibit high sensitivities to temperature and refractive index, respectively. Specifically, both modes are sensitive to temperature with sensitivities of 0.072 nm/K and 0.0778 nm/K, while only Mode 2 is sensitive to refractive index with a high sensitivity of 361.25 nm/RIU, enabling data decoupling via the establishment of a two-dimensional sensitivity matrix. This fiber tip features a stable structure, simple operation and excellent dynamic response to temperature variations, which is expected to provide a novel technical solution for high-precision multi-parameter measurement. More applications can be further expanded by optimizing the structural parameters and fabrication processes in the future.