Fiber-top refractometer

Abstract

We present a fiber-top device designed to measure variations of the refractive index of a liquid in which it is immersed. The sensitivity achieved with this first prototype is on the order of one part over 105 in a 30 kHz bandwidth. With a proper design, the device performs well also when immersed in liquids with refractive index equal to the refractive index of the core of the fiber.