All photonic bandgap fiber spectroscopic system for detection of refractive index changes in aqueous analytes

Qu, Haiyan; Ung, Bora; Rozé, Mathieu; Skorobogatiy, Maksim

doi:10.1016/j.snb.2011.10.025

Cited by 15 publications

(10 citation statements)

References 31 publications

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“…However, in the practical capillary sensor, many high-order modes could be excited in the core due to the large diameter of the capillary. These high-order modes with smaller fraction of power overlapping with the test analytes (i.e., gaseous samples) filled in the capillary are less sensitive to changes in the refractive index of the analytes as compared to the fundamental mode, thus resulting in a smaller number of fringe shifts [25]. In Figure 4b, the refractive index of the air in the capillary core features an almost perfect linear response to the fringe shifts counted.…”

Section: Resultsmentioning

confidence: 97%

Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer

Chen

et al. 2020

Sensors

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In this paper, we report a capillary-based Mach–Zehnder (M–Z) interferometer that could be used for precise detection of variations in refractive indices of gaseous samples. The sensing mechanism is quite straightforward. Cladding and core modes of a capillary are simultaneously excited by coupling coherent laser beams to the capillary cladding and core, respectively. An interferogram would be generated as the light transmitted from the core interferes with the light transmitted from the cladding. Variations in the refractive index of the air filling the core lead to variations in the phase difference between the core and cladding modes, thus shifting the interference fringes. Using a photodiode together with a narrow slit, we could interrogate the fringe shifts. The resolution of the sensor was found to be ~5.7 × 10−8 RIU (refractive index unit), which is comparable to the highest resolution obtained by other interferometric sensors reported in previous studies. Finally, we also analyze the temperature cross sensitivity of the sensor. The main goal of this paper is to demonstrate that the ultra-sensitive sensing of gas refractive index could be realized by simply using a single capillary fiber rather than some complex fiber-optic devices such as photonic crystal fibers or other fiber-optic devices fabricated via tricky fiber processing techniques. This capillary sensor, while featuring an ultrahigh resolution, has many other advantages such as simple structure, ease of fabrication, straightforward sensing principle, and low cost.

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Section: Resultsmentioning

confidence: 97%

Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer

Chen

et al. 2020

Sensors

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“…In such a fiber light is guided in the hollow-core due to the photonic band gap of a Bragg mirror applied onto the inner capillary wall. HCBFs have been tested for refractive-index [19,20], and absorption-based sensing [21].…”

Section: Sensor Setupmentioning

confidence: 99%

Extrinsic Fiber-Optic Sensor for Detection of Saliva pH

et al. 2019

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Measurements of pH are important in industry, agriculture, medicine, etc. Two main principles, namely electrochemical and optical ones, have been employed in pH meters and sensors. This paper is aimed at the development of extrinsic fiber-optic sensors of saliva pH. Such sensors have already been used for monitoring pH changes caused by biological processes. In this paper, fiber-optic sensors consisted of inlet and outlet silica fibers transmitting light from a halogen lamp to a sample cell and then to a diode-array spectrometer. Two types of sample cells were used; namely a silica cell with a measurement path of 10 mm, and a special silica capillary cell with a hole diameter of 0.07 mm and measurement path up to 40 mm. This capillary, produced at the Institute, consists of a Bragg mirror applied onto the inner silica capillary wall. Both the sensors were calibrated by using Sorensen buffers with bromothymol blue and a commercial pH meter. The calibration curves were used for the determination of pH of saliva samples collected from one healthy person at different times. It has been found that the fiber-optic sensors provide us with lower pH values than the pH meter. This result can be explain by effects of saliva components on bromothymol blue spectra. By using a correlation line between pH values measured by the sensors and those from the pH meter the sensor reliability of about 0.3 pH units can be estimated.Keywords Fiber-optic sensor · Rectangular cell · Bragg capillary cell · Sorensen buffer · Bromothymol blue · Saliva pH Paper based on an Invited Lecture presented at MADICA

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“…2 Most of today's modern optical spectroscopes are founded upon Fraunhofer's diffraction principle except for a few noble instruments such as the Fourier transform infra-red spectroscope, fiber Bragg grating spectroscope and Raman spectroscope. [3][4][5][6][7][8][9][10] In Fraunhofer diffraction, the first order diffracted light has an angular dispersion with respect to the wavelength of light. Periodic linear lines, with constant gap spacing, reflect and diffract incoming photons into different angles with respect to the wavelengths.…”

Section: Historical Background and Mathematical Foundation Of Spectromentioning

confidence: 99%

Miniaturization of optical spectroscopes into Fresnel microspectrometers

Park

Choi

2013

J. Nanophoton

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Abstract. Miniaturized optical instruments have become very important in industry as smart phones and tablet PCs increase in popularity. A chronology of spectrometer development shows that a simple numerical point of view affords important insights. A tiny spectrometer, which is smaller than a few millimeters size, cannot easily rely on the conventional Fraunhofer diffraction due to its optical criterion limit. As an alternate solution to build smaller spectrometers, a Fresnel spectrometer chip with a gradient line grating is attractive. The fabri-cated Fresnel spectrometers have optical path volumes of about 1 mm3 and spectral resolutions of 10 to 23 nm. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the origi-nal publication, including its DOI. [DOI: 10.1117/1.JNP.7.077599

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All photonic bandgap fiber spectroscopic system for detection of refractive index changes in aqueous analytes

Cited by 15 publications

References 31 publications

Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer

Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer

Extrinsic Fiber-Optic Sensor for Detection of Saliva pH

Miniaturization of optical spectroscopes into Fresnel microspectrometers

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