A. W. Palmer’s research while affiliated with City, University of London and other places

... The effect of high temperature on sensors based on commercial erbium-doped fibers, at temperatures up to 11008C, has been discussed in a comprehensive paper by w x Zhang et al. 138 . The underpinning science of the luminescent effects in such fibers, for example considering the influence of the upper levels of erbium doped into silica fibers, has been explored by authors such as Mazzali et al. ...

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Fiber Optic Sensor Technology: An Overview

... Different sensing elements schemes are proposed since then, such as ring-shaped sensing element [2] , triangular-shaped bulkoptic sensing element [3] , etc. Sensing element with polarization-preserving coating surfaces, presenting inFig. 1, was proposed by Wang et al. [4]. The light beam coming from an optical source is put into the sensing head through a piece of optic fiber. ...

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Theoretical analysis of the temperature characteristics of an optical current sensing element

... We show good agreement between the theory and experimental data, demonstrating that the line shift can be used as a potential thermal sensor. This can be compared to other methods [21]. The authors thank William S. Luck and William C. Edwards for their support. ...

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Spectroscopy of BeAl(2)O(4):Cr(3+) with application to high-temperature sensing

... retained in the sediment through adsorption onto Fe-oxyhydroxides leading to C org /P ratios lower than the Redfield ratio (Algeo and Ingall, 2007;Kraal et al., 2012 and references therein). Our high C org /P (up to ~1293) are close to that of the Upper Silurian-Lower Devonian graptolitic shales from Poland (C org /P = 151-1477, mean 977, Porebska and Sawlowicz, 1997), collectively indicating prevalent anoxic depositional conditions. By contrast, the wide range of Mo values (3-72 ppm; Fig. 9) and EFs detected in the Liblín black shales indicate changes of non-euxinic with intermittently euxinic depositional conditions (e.g, Scott and Lyons, 2012). ...

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Elemental and isotopic compositions of trench-slope black shales, Bohemian Massif, with implications for oceanic and atmospheric oxygenation in early Cambrian

... This section consists of a thick "siliciclastic unit" (SU) occurring within an alternation of marls and marly limestones, with intercalated thin-bedded turbidites (Fig. 5). The SU is ascribed to the PETM based on biostratigraphically constrained isotopic profiles of whole-rock carbonate samples (Schmitz et al., 1997) and dispersed organic carbon (Storme et al., 2012). The Zumaia section is one of robust temporal framework for this event (Dunkley Jones et al., 2018). ...

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Mercury enrichments of the Pyrenean foreland basins sediments support enhanced volcanism during the Paleocene-Eocene thermal maximum (PETM)

... The magnitude of their changes may be adjusted and controlled relative to the output light intensity. To achieve this, light from a laser diode was linearly polarised and launched in one of the two eigenmodes of the Hi-Bi fibre employed [5]. The power coupled into the second eigenmode providing the required information on the applied environment of the coupling device. ...

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FIBRE OPTIC FORCE SENSOR AND ITS APPLICATIONS

... In recent years, thulium-doped fiber lasers (TDFLs) operating at the 2 µm wavelength, which is safe for the human eyes and falls within a low-loss atmospheric window, have become a hot topic for researchers due to their wide applications such as laser atmospheric communication [1], biomedicine [2], and military [3]. The demand for high beam quality and low-loss transmission at 2 µm has imposed greater requirements on fibers. ...

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Nested hollow-core anti-resonant fiber with elliptical cladding for 2 µm laser transmission

... Ono-exponential decay signal is quite common in cavity ring-down spectroscopy [1], [2], nuclear radioactive decay [3], and fluorescence decay analysis [4], etc. For a mono-exponential decay, the decay rate is mainly focused because it takes the information for research. ...

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The Extreme Learning Machine for the Extraction of Mono-Exponential Decay Time

... For example, the burst effect of Er 3+doped YAG above 600 °C causes rapid decay of fluorescence intensity and fluorescence lifetime, resulting in different sensitivity of the sensor in different temperature intervals [61]. Tm-doped Y2O3 has a weak fluorescence intensity, so the signal-to-noise ratio of the detected signal is poor and not suitable for high-precision measurements [62]. Therefore, The FIR method achieves temperature testing by detecting the fluorescence intensity ratio of two wavelengths at different excited states. ...

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Optical Fiber Sensors for High-Temperature Monitoring: A Review

... Luminescence decay-based fiber optic thermometers have attracted considerable interest for their ability to probe temper atures in harsh environments where their immunity to chemical attack and electromagnetic interference as well as minimal intrusiveness are significant advantages over either thermocouples or electrical-resistance based thermometers [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. While single fiber probe configurations for luminescence-based fiber optic thermometers as well as for fluorescence and Raman probes have been recognized to offer advantages of simple design, compactness, perfect excitation/ collection zone alignment, and high light collection efficiency, their effective use has been greatly limited by background interference by emission or scattering generated in the fiber probe itself as well as the excitation and collection fibers coupled to the probe [15][16][17][18][19][20]. ...

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Single fiber temperature probe configuration using anti-Stokes luminescence from Cr:GdAlO3