Dear Steemian,
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In this review, I present POF Optical sensor based intrinsic sensor which have been widely employed as media of sensor with diverse application in different field. Including utilize as gas or VOCS (volatile organic compounds) detection, ph, toxic in chemical liquid that’s has number of permissible exposure limit. POF has many advantages as optical probe such as high crack robustness, high elastic strain, and high bending flexibility. This article describe up to date research with varies kind type of detection model, and numerous sensitive material use as coating to enhance sensitivity and selectivity of optical probe itself during measurement process from the available literature. This paper is a review of recent work of Polymer Optical research based intrinsic sensor on varies field application.
Utilization Polymer optical fibre (POFs) as sensor have authorized for detection of an important hazardous material in gas form or liquid in several application. For optimal employment of POF sensor, several distinctive such as sensitivity, selectivity, time response and detectivity must be concentrate concurrently. The most serious issue for realization of sensor in term of good sensitivity, selectivity, and maintain the sensing method with every condition need. Sensitivity consent to ratio change of sensor its self to value of measuring particular gas or liquid chemical compound, selectivity allow the sensor only to detect one particular compound in the existence of others, and detectivity allow sensor to detect slightest presence of gas and another particular chemical compound [1].
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There are two general approaches to enhance sensor performance first, preparing a specifically sensitive to one chemical compound and has zero cross- sensitivity to enhance selectivity to another different compound presence whilst measurement phase. Second preparation of, materials which proficient to distinguish varies kind of analyte in a combination such distinguish is possible because of different characterization of the analyte to the materials [2].The advantage of Polymer optical sensing in gas and liquid sensor are well known and these comprise to the POF advantages are light weight, anti-electromagnetic interference, multiplicity capacity, transportable, on line monitoring. These properties became a great potential to polymer optical fibre as intrinsic sensor, beside the advantage of easy fabrication as sensor compare to fibre optic silica [3]. and, became a great competitor for electronic sensor.
Intrinsic Probe Geometric
In a intrinsic polymer optical fiber sensor, The POF role as the conversion of gas or liquid of chemical concentration into optically determined information of chemical in a sample into optically data measurement. The main transduction principles employ by these type of sensing method is the evanescent field that’s interact with the sensing target by utilizing propagation light which radiated out from the modified cladding. The natural condition occurred whereas non-oscillatory electromagnetic field which expands outside the fibre core is often utilized to couple the optical field [4].
The sensing technique developed expansively using many different type of spectroscopic technique. Plastic optical fibre modifications and sensitive coating material deposition onto fibre surface as interaction between sensor probe and the target gases or liquid. Several sensing method previously employed Absorbance[5][6],reflectance[2], fluorescence[7], surface Plasmon resonance (SPR)[8]. Besides using different method of sensing to enhance the performance of the sensor itself, deposition of different kind of sensitive material and selection of chemical material depend on sensitiveness of material.
Modified a probe sensor is the important step in term of producing a better quality of intrinsic fibre sensor probe there are some technicalities employed earlier by many researchers namely, chemical etching[9], mechanical etching[5], and tapering[10]. This step has its own level of technical intricacy. In chemical etching process, while dipping polymer optical fibre into organic chemical solvent that’s react as an etchant liquid. The steps process to etch layer by layer the cladding surface must be employed properly to avoid fibre breakage inside chemical solvent. Acetone widely use as chemical etchant in many study of polymer optical fibre etching [11], the temperature and immersing time is the main thing that’s must be controlled precisely. In Mechanical etching sand paper and polishing film utilized to remove layer of cladding, this step must be done in low speed to possess uniform removal rate and scratch-free layer of polymer optical fiber. Producing tapered fiber using tapering machine was introduced formerly using fiber optic silica, this is done as alternative technique, because of difficulty in producing fiber taper from silica type, and chemical etching of silica using hydrofluoric acid that’s harm to human body.
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Geometrical aspect of plastic optical fibre also studied extensively by Leung, A., et al., in term of designing proper sensor with high enhancement performance,[12][13][14]. This study applied based on variety of fibre material, numerical aperture, core size and the thickness of cladding. de Nazare, F.V.B., et al have been evaluated the performance of two different types of geometrical shape of intrinsic sensor, namely U-Shape and straight. The fibre afterwards tested using different concentration of sucrose to observe performance of booth intrinsic sensor within different geometric.
Geometrical shape, modification technique and sensing technique are important key in Designing proper polymer optical fibre sensor, therefore the determination of better performance sensor depend on target of the sensing and placement of the sensor during the sensing process. Certainly this fibre intrinsic sensor rapidly improves their performance with different type of sensitive material uses to enhance the work of sensor in targeting the chemical compound.
conclusion
Fiber optic is the medium that apply as a sensor with various type of geometric, the purpose of modification is to obtain the targeted sensor object in targeting a volatile organic compound. sensor based fiber is a research area that employ by many researcher in varied field of work. in the next post I will review regarding sensing method of fiber optic.
Reference
[1] https://www.google.com/books?hl=en&lr=&id=KtRZeOGS8fkC&oi=fnd&pg=PR5&dq=Vaezi-Nejad,+S.M.,+Selected+topics+in+advanced+solid+state+and+fibre+optic+sensors.+2000:+IET&ots=2WXgoEKb1B&sig=Jj
[2] https://www.nature.com/articles/srep01868/fig_tab
[3] https://www.osapublishing.org/abstract.cfm?uri=col-12-4-043002
[4] https://www.sciencedirect.com/science/article/pii/0925400593852375
[5] https://www.sciencedirect.com/science/article/pii/S0925400511003285
[6] https://www.sciencedirect.com/science/article/pii/S156717391300463X
[7] https://www.sciencedirect.com/science/article/pii/S0924424711007424
[8] https://www.sciencedirect.com/science/article/pii/S0925400512005886
[9] https://www.sciencedirect.com/science/article/pii/S0030402612002069
[10] https://www.sciencedirect.com/science/article/pii/S1068520010000805
[11] https://www.sciencedirect.com/science/article/pii/S0030402613010875
[12] http://ieeexplore.ieee.org/abstract/document/5944172
[13] https://www.sciencedirect.com/science/article/pii/S095656630500374X
[14] https://www.sciencedirect.com/science/article/pii/S0925400501009959
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