Fiber-Optic Refractive Index Sensor Based on the Cone-Based Round Structure

Fiber-optic refractive index (RI) sensors have the advantages of low cost, simple optical setup, remote sensing, and simple fabrication. A cone-based round structure, which is the combined structure of the cone structure and the round structure, is successively fabricated by using a cleaving method, a chemical glass etching method, and an electrical arc discharge method. In order to examine the possibility of the RI sensor, the fabricated cone-based round structure is used for the detection of various RIs by measuring the reflected intensities in the target sensing media. In addition, a fiber-optic localized surface plasmon resonance (LSPR) sensor based on the cone-based round structure is fabricated to enhance the sensitivity regarding RI changes. The fabricated fiber-optic LSPR sensor is used to detect the change of the RIs using the shift of peak wavelengths, as well as the change of reflected resonance intensities, by measuring LSPR spectra for gold nanoparticles on it.