TY - JOUR

T1 - Mid-infrared silver halide fibre-optic sensor with lateral notches for evanescent wave spectroscopy

AU - Korsakova, Elena

AU - Yuzhakova, Anastasia

AU - Salimgareev, Dmitrii

AU - Lvov, Alexander

AU - Zhukova, Liya

AU - Korsakov, Alexandr

N1 - The research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program) is gratefully acknowledged.

PY - 2023/1

Y1 - 2023/1

N2 - In this study, we developed mid-infrared U-shape fibre sensing elements intended for fibre evanescent wave spectroscopy (FEWS). The sensing elements possess increased efficiency due to adding small notches on the fibre's lateral surface. The fibre tips were made of AgCl0.25Br0.75 – AgI ceramic, and we provided the complete production cycle from the synthesis of raw materials to the extrusion of fibres and the manufacture of final products. First, using COMSOL Multiphysics software, we simulated the mode field distribution of the sensing elements plunged into an ethanol solution to choose the best bending radius. Then, we fabricated three different variants of sensing elements: with small notches, with large notches, and without them. Further, we recorded the transmission spectra of ethanol and assessed the sensors’ performance as a product of the signal-to-noise ratio and the height of the ethanol absorption peak. It was revealed that the sensing element with large notches is less efficient than the U-shape fibre tip with a smooth lateral surface, whereas the sensing element with small notches is three times more efficient when compared to the conventional one with a smooth lateral surface. Thus, the experiments showed that it is reasonable to modify the side surface of fibre-optic tips, but it is essential to carefully select the extent of the modification to achieve the highest possible sensor efficacy.

AB - In this study, we developed mid-infrared U-shape fibre sensing elements intended for fibre evanescent wave spectroscopy (FEWS). The sensing elements possess increased efficiency due to adding small notches on the fibre's lateral surface. The fibre tips were made of AgCl0.25Br0.75 – AgI ceramic, and we provided the complete production cycle from the synthesis of raw materials to the extrusion of fibres and the manufacture of final products. First, using COMSOL Multiphysics software, we simulated the mode field distribution of the sensing elements plunged into an ethanol solution to choose the best bending radius. Then, we fabricated three different variants of sensing elements: with small notches, with large notches, and without them. Further, we recorded the transmission spectra of ethanol and assessed the sensors’ performance as a product of the signal-to-noise ratio and the height of the ethanol absorption peak. It was revealed that the sensing element with large notches is less efficient than the U-shape fibre tip with a smooth lateral surface, whereas the sensing element with small notches is three times more efficient when compared to the conventional one with a smooth lateral surface. Thus, the experiments showed that it is reasonable to modify the side surface of fibre-optic tips, but it is essential to carefully select the extent of the modification to achieve the highest possible sensor efficacy.

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85145264525

U2 - 10.1016/j.infrared.2022.104529

DO - 10.1016/j.infrared.2022.104529

M3 - Article

VL - 128

SP - 104529

JO - Infrared Physics and Technology

JF - Infrared Physics and Technology

SN - 1350-4495

ER -