A refractive index sensor based on the leaky radiation of a microfiber

TL;DR

This paper introduces a simple, highly sensitive refractive index sensor using leaky radiation from a microfiber, capable of detecting minute changes in liquid refractive index with high precision.

Contribution

The work demonstrates a novel microfiber-based sensor utilizing leaky radiation for precise refractive index measurement, with theoretical sensitivity over 400 degrees/RIU.

Findings

Refractive index variation of 0.001 can be detected

Sensor sensitivity exceeds 400 degrees/RIU theoretically

Simple fabrication process for the microfiber sensor

Abstract

In this work we present a refractive index sensor based on the leaky radiation of a microfiber. The 5.3um diameter microfiber is fabricated by drawing a commercial optical fiber. When the microfiber is immersed into a liquid with larger refractive index than the effective index of fiber mode, the light will leak out through the leaky radiation process. The variation of refractive index of liquid can be monitored by measuring radiation angle of light. The refractive index sensitivity can be over 400 degree/RIU in theory. In the experiment, the variation value 0.001 of refractive index of liquid around this microfiber can be detected through this technique. This work provides a simple and sensitive method for refractive index sensing application.