Fiber optic evanescent field sensor for detection of explosives and CO2 dissolved in water

Orghici, Rozalia; Willer, Ulrike; Gierszewska, M.; Waldvogel, Siegfried R.; Schade, Wolfgang

doi:10.1007/s00340-008-2932-7

Cited by 65 publications

(40 citation statements)

References 9 publications

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“…First investigations regarding the optical detection of the intercalation between receptor and TNT were performed via evanescent field spectroscopy by using a bare silica multimode fiber coated with the synthesized receptor molecules [96]. The sensing of species using this spectroscopic method is based on the interaction between the light guided within an optical waveguide, for example, fiber, and the surrounding medium, which occurs upon total internal reflection at the interface between two media with different index of refraction.…”

Section: Photonic Ring Resonator Sensorsmentioning

confidence: 99%

“…For this purpose, a frequency doubled passively Q-switched Cr 4 þ : Nd 3 þ : YAG microchip laser (emission wavelength l 1 ¼ 1064 nm and frequency doubled to l 2 ¼ 532 nm) was used as light source, enabling the simultaneous measurement at both wavelengths and showing the wavelength sensitivity and selectivity of this sensor concept, since changes in the signal intensity were measured only by the interaction of the green light with TNT, whereas the intensity of the infrared light remained constant. The registered changes in the signal can be attributed to the formation of the colored chargetransfer complex between the receptor and TNT molecules that has its absorption peak around 532 nm [96]. However, even though this sensor concept allows the identification of TNT, the implementation of optical fibers as detection devices is not very convenient for field applications, because their sensitivity depends on the penetration depth of the evanescent field, which is connected to the acceptance and additionally the coupling angle of the fiber.…”

Section: Photonic Ring Resonator Sensorsmentioning

confidence: 99%

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Detection of Explosives

Schade

Orghici

Mordmüller

et al. 2012

Handbook of Biophotonics

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Nowadays, much attention is given to the detection of explosives in order to prevent terrorist activities and assure security at airports, aviation, public transportation, convention halls, concerts, and so on. The location of undetonated and buried landmines is also a matter of great importance that could help to minimize fatalities and injuries among civilians caused by mines detonating. Another problem related to the use of explosives is the fact that nitrogen-based explosives, such as trinitrotoluene (TNT), are toxic and able to rapidly penetrate the skin, leading to significant health problems [1,2]. For this reason, the sensing of hazardous substances may be of great interest at many facilities, where explosive materials were/are still manufactured and deposited, in order to avoid contamination of the soil or groundwater with the toxic compounds that can result from improper waste disposal, and to ensure the safety of both workers and nearby residents.As can be seen, the detection of explosives is a significant task in the field of security and environmental analysis. Over the last several years major efforts have been focused on developing innovative sensing devices, capable of detecting hazardous species. In contrast to commonly used methods, such as ion mobility spectrometry (IMS), gas chromatography, or mass spectrometry, that require sampling for performing analysis and are relatively cost-intensive, optical methods are ideally suited for a fast online and in situ detection of hazardous substances due to their contact-free and nondestructive operation.However, at the present time, there is no sensing system available which can identify all explosive compounds, promising high sensitivity, selectivity, and low false-alarm rate, simultaneously. Depending on the nature of the applications, sensing devices based on different laser spectroscopic methods have been developed, each of them offering high efficiency for a specific type of explosive material. A reliable detection of explosive traces in the vapor phase or in the form of particles, essential for security applications, can only be achieved by combining the sensing methods and their respective features. In the following, an overview of several laser-

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Section: Photonic Ring Resonator Sensorsmentioning

confidence: 99%

Section: Photonic Ring Resonator Sensorsmentioning

confidence: 99%

Detection of Explosives

Schade

Orghici

Mordmüller

et al. 2012

Handbook of Biophotonics

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“…Optical fibres are particularly suited because they allow for remote analyte detection, as well as having the ability to be functionalised for specific and sensitive binding of vapour or liquid explosives. Indeed, a plethora of fibre optic sensors exist for such purposes (see, for example [3][4][5][6] ).…”

Section: Introductionmentioning

confidence: 99%

Fibre loop cavity ring-down spectroscopy for the sensitive and selective detection of minute sample volumes of liquid explosives

Rushworth

Vallance

2010

Optics and Photonics for Counterterrorism and Crime Fighting VI and Optical Materials in Defence Systems Technology VII

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Fibre loop cavity ring-down spectroscopy (FLCRDS) is a relatively new technique, which extends the more commonly used two-mirror cavity ring-down spectroscopy (CRDS) technique to measurements of optical absorption by minute liquid sample volumes. In this paper, loops of 50 μm-core-diameter multimode optical fibre were used to carry out both direct and evanescent wave FLCRDS measurements at 532 nm. The sensitivity of each technique was established by making measurements on a common dye, rhodamine 6G; detection limits were found to be in the micromolar range for aqueous rhodamine, in a sample volume of only a few picolitres. In this case, evanescent wave FLCRDS was found to be more sensitive than direct absorption. Functionalisation of the silica taper used for evanescent absorption measurements allows for binding measurements to be carried out. We report the results of preliminary proof-of-concept measurements on the binding of streptavidin to a biotinylated taper.

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“…Owing to advancements in technology and materials (especially optic fiber) during the last decade, various chemical sensors are currently available for measuring real-time in situ dissolved CO 2 in water [9,10]. The primary goals of this study are to (1) address sensitivity of geochemical parameters to CO 2 leakage based on theoretical analysis; and (2) assess whether fiber optic CO 2 sensors can be used for real-time in situ monitoring of CO 2 leakage signals which were simulated through two pulse-like CO 2 release tests.…”

Section: Introductionmentioning

confidence: 99%

Monitoring dissolved CO2 in groundwater for CO2 leakage detection in a shallow aquifer

et al. 2014

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This study presents demonstration of monitoring dissolved CO 2 using fiber-optic CO 2 sensors for CO 2 leakage detection through a small-scale field test. Theoretical analysis of CO 2 leakage into a potable aquifer system with and without the presence of carbonates in the aquifer sediments suggests that dissolved CO 2 is a good indicator of CO 2 leakage. CO 2 leakage was simulated through two pulse-like CO 2 releases into a single testing well which were monitored with a fiber-optic CO 2 sensor and periodic groundwater sampling. Field results show that the changes in dissolved CO 2 concentrations were detected by the CO 2 sensor, confirming that it is possible to use chemical sensors for real-time in situ leakage detection at a geological carbon sequestration site.

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Fiber optic evanescent field sensor for detection of explosives and CO2 dissolved in water

Cited by 65 publications

References 9 publications

Detection of Explosives

Detection of Explosives

Fibre loop cavity ring-down spectroscopy for the sensitive and selective detection of minute sample volumes of liquid explosives

Monitoring dissolved CO2 in groundwater for CO2 leakage detection in a shallow aquifer

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