A review: Development of novel fiber-optic platforms for bulk and surface refractive index sensing applications

Abstract

The expanding role of refractive index measurement in many fields including chemistry, biology and medicine, food industry, process control, and environmental monitoring, has led to a growth of research and development efforts in this field. Optical fibers represents a very promising platform for refractive index sensing due to appealing features such as high sensitivity, small fingerprint, high degrees of integration, compatiblity in harsh environments, and potential to provide real time and remote analysis. Up to date, a wide range of fiber-optic refractive index sensors based on different configurations and mechanisms have been proposed and developed. In this paper, we aim to review the most commonly-used fiber-based refractive index sensors operating in visible and infrared regions, and briefly summarize their advantages and limitations. Furthermore, since THz waves have prominent advantages such as extended probing length, no damage to biological samples, unique fingerprint of biological samples, and non-ionizing feature, we then proceed to review the recent development of several categories of THz waveguide platforms for refractive index sensing applications. Finally, we summarize the review work and present the future perspectives of this field.