Micro and Nanostructured Materials for the Development of Optical Fibre Sensors

Abstract

The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface. This review reveals some of the main techniques that are currently been employed to develop this kind of sensors, describing in detail both the resulting supporting matrices as well as the sensing materials used. The main objective is to offer a general view of the state of the art to expose the main challenges and chances that this technology is facing currently.

Optical Fiber Temperature Sensors and Their Biomedical Applications

“…The main configurations of the MMI structures are simple and enable the detection of a change in the refractive index of the surrounding medium, i.e., due to the high interaction of the evanescent field with the external environment. The manufacturing of new concepts of MMIs can be greatly enhanced through the combination of fiber optics with nano-structure technology and the use of sensitive thin films [86][87][88][89]. Sensors based on MMI, allied with the functionalization with thin films as sensitive elements, could open new fields for optical fiber sensor applications.…”

Label-Free Optical Resonator-Based Biosensors

“…An optical fiber was originally developed to guide light waves along the core, which is surrounded by a cladding layer through the total internal reflection at the interface with negligible loss. Over the last few decades, optical fibers have been extensively investigated for biosensing applications, with the intrinsic advantages including flexibility, low-cost, small size, and biocompatibility [ 39 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 ]. To be developed as a biosensor, the structure of optical fiber has modified to maximize the interaction of light with target analytes and increase the sensitivity [ 66 ].…”

Low‐Coherence Interferometer with Nanocrystalline Diamond Films with Potential Application to Measure Small Biological Samples

“…Growing demand for precise measurements in industry and medical diagnostics has stimulated research on optical fiber sensors, in particular the research on using new materials in these sensors . The most popular group of fiber‐optic sensors is based on the fiber‐optic interferometers.…”