Multi-functional optical sensor based on plasmonic photonic liquid crystal fibers

A novel design of compact surface plasmon resonance multifunctional biosensor based on liquid crystal (LC) photonic crystal fiber (PCF) is proposed and studied. The suggested sensor has a central hole filled with LC as a temperature dependent material. Further, another large hole filled with liquid analyte has a gold nanorod as a plasmonic material. Therefore, the proposed senor can be used for temperature and analyte refractive index sensing via the coupling between the core guided modes in the LC core and the surface plasmon modes around the nano gold rod. The effects of the structure geometrical parameters are studied to maximize the sensitivity of the LC PCF biosensor. The numerical analysis is carried out using full-vectorial finite element method with perfectly matched layer boundary conditions. The reported multifunctional sensor offers high sensitivity of 5 nm/°C and 3700 nm/RIU (refractive index unit) for temperature and analyte refractive index sensing, respectively. To the best of the authors’ knowledge, it is the first time to introduce PCF biosensor with high sensitivity for temperature and analyte refractive index sensing as well.