Miniature pH optical fiber sensor based on waist-enlarged bitaper and mode excitation

Wong, Wei Chang; Chan, Chi Chiu; Hu, Pengbing; Chan, Jin Rong; Low, Yi Ting; Dong, Xuelin; Leong, K. C.

doi:10.1016/j.snb.2013.10.045

Cited by 32 publications

(13 citation statements)

References 37 publications

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“…Interferometric sensing was accomplished, 182 for example, by using a waist-enlarged bitaper modified with a tantalum pentoxide layer that displays high refractive index (RI). It was coated with a poly(vinyl alcohol)/poly(acrylic acid) composite hydrogel to induce sensitivity to pH in the pH 2.5–6.5 range.…”

Section: Commonly Used Optical Sensing Schemesmentioning

confidence: 99%

“…An example of an interferometric pH sensor is represented by a fiber sensor based on the use of waist-enlarged bitapers and mode excitation. 182 The interferometer, which comprises a waist-enlarged bitaper, a round tip, and a tantalum pentoxide layer displays high refractive index (RI) sensitivity. It was coated with a poly(vinyl alcohol)/poly(acrylic acid) composite hydrogel to induce sensitivity to pH values.…”

Section: Sensing Formatsmentioning

confidence: 99%

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Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

2020

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This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and p K a values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.

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Section: Commonly Used Optical Sensing Schemesmentioning

confidence: 99%

Section: Sensing Formatsmentioning

confidence: 99%

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

2020

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“…Changes in RGB values could be identified for the color-change range of each indicator, in the acidic, neutral, and basic regimes. Methyl orange has a color-change of pH 2-8, bromthymol blue has a range near neutrality of pH 3-7, and phenolphthalein has a range of pH [8][9][10][11]. The values of G in particular tend to increase or decrease clearly over most of each range.…”

Section: Methodsmentioning

confidence: 99%

“…So far, several types of pH sensor have been developed, ranging from pH strips with low precision to precise pH meters using glass electrodes [7][8][9][10][11][12]. A pH meter is a device for measuring the hydrogen-ion concentration accurately, but the electrodes of a pH meter have the disadvantage of being broken easily by slight shock.…”

Section: Introductionmentioning

confidence: 99%

An Array-Type RGB Sensor for Precision Measurement of pH

Kim

et al. 2015

Journal of the Optical Society of Korea

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As pH is a widely used index in chemical, medical, and environmental applications, research on pH sensors has been active in recent years. This study obtained RGB values by measuring the reflected light from a liquid sample to detect fine changes in pH, and performed mathematical modeling to investigate the relationship between the detected optical signal and pH value. Also, the trends in pH changes were easily identified by analyzing RGB values and displaying them in the color coordinate for easy visualization of data. This method implemented a user-friendly system that can measure and analyze in real time. This system can be used in many fields such as genetic engineering, environmental engineering, and clinical engineering, because it not only can measure pH but also replaces a colorimeter or turbidimeter.

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“…Many different geometries have been explored to create modal fiber interferometers that are sensitive to the refractive index (RI) surrounding the sensor. For all of them a core mismatch that causes cladding modes to be excited, either through a waist-enlarged bitaper [2], sections of multi-mode (MM) fiber [3], coreless fiber [4], or with a thin-core fiber [5,6], the method in this work. These types of sensors have attracted a lot of attention due to their simplicity of both fabrication and operation, in addition to the general advantages of fiber optic sensors.…”

Section: Introductionmentioning

confidence: 99%

Combined temperature and RI sensor for exploring the phase transitions of ethanol solutions

Wahl

Wilhelmsen

Hjelme

2018

26th International Conference on Optical Fiber Sensors

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Miniature pH optical fiber sensor based on waist-enlarged bitaper and mode excitation

Cited by 32 publications

References 37 publications

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

An Array-Type RGB Sensor for Precision Measurement of pH

Combined temperature and RI sensor for exploring the phase transitions of ethanol solutions

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