A new fiber sensor system designed for spectroscopic analysis and on-line quality assurance of arc-welding processes is presented here. Although several different approaches have been considered for the optical capture of plasma emission in arc-welding processes, they tend to be invasive and make use of optical devices such as collimators or photodiodes. The solution proposed here is based on the arrangement of an optical fiber, which is used at the same time as the optical capturing device and also to deliver the optical information to a spectrometer, embedded within an arc-welding torch. It will be demonstrated that, by using the shielding gas as a protection for the fiber end, the plasma light emission is efficiently collected, forming a sensor system completely transparent and noninvasive for the welding operator. The feasibility of the proposed sensor designed to be used as the input optics of a welding quality-assurance system based on plasma spectroscopy will be demonstrated by means of several welding tests.
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http://dx.doi.org/10.1364/ao.46.003215 | DOI Listing |
Advancements in plasmonic sensing require simultaneous detection capability that ensures large-scale detection with reduced losses. In this work, we propose a new solid-core fiber-based refractive index (RI) sensor with an ultra-broad detection range. The proposed fiber consists of a relatively simple single-ring cladding with six circular tubes in which the light is guided in the core based on the inhibited-coupling (IC) mechanism.
View Article and Find Full Text PDFInspired by human skin, bionic tactile sensing is effectively promoting development and innovation in many fields with its flexible and efficient perception capabilities. Optical fiber, with its ability to perceive and transmit information and its flexible characteristics, is considered a promising solution in the field of tactile bionics. In this work, one optical fiber tactile sensing system based on a flexible PDMS-embedded optical fiber ring resonator (FRR) is designed for braille recognition, and the Pound-Drever-Hall (PDH) demodulation scheme is adopted to improve the detection sensitivity.
View Article and Find Full Text PDFpH is an important physiological parameter within organisms, playing a crucial role in functional activities in cells and tissues. Among various pH sensing methods, optical fiber pH sensors have gained a wide attention due to their unique advantages. However, current silica optical fiber-based pH sensors face some challenges such as weak biocompatibility, low biological safety, complex or unstable surface modification.
View Article and Find Full Text PDFThe detection of mercury ions (Hg) is crucial due to its harmful effects on health and environment. In this article, what we believe to be a novel dual-mode optical fiber sensor incorporating surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS) is proposed for ultra-trace Hg detection. The sensing probe comprises gold (Au)/graphene oxide (GO) composite membrane structure and Au nanospheres (AuNPs), which are connected via double-stranded DNA.
View Article and Find Full Text PDFWe propose and experimentally demonstrate what we believe to be the first mid-infrared surface plasmon resonance (SPR) fiber optic sensor using a D-shaped multimode silica optical fiber coated with a 105 nm indium tin oxide (ITO) layer. The sensor shows resonance around 2700 nm, with a refractive index sensitivity of 1065.70 nm per refractive index unit (nm/RIU) for refractive indices ranging from 1.
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