High performance chitosan diaphragm-based fiber-optic acoustic sensor

Chen, L.H.; Chan, Chi Chiu; Yuan, Wu; Goh, S.K.; Sun, Jian

doi:10.1016/j.sna.2010.06.023

Cited by 94 publications

(40 citation statements)

References 13 publications

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“…1] ensures an excellent sealing of the glass structure: this leads to a small thermal coefficient, and remarkable stability even in long operations. The mechanical strength of the glass diaphragm is sufficient to sustain the insertion and pressure application in the liver tissue, as opposed to flexible diaphragms [23] that are excessively fragile for insertion.…”

Section: Sensor Fabricationmentioning

confidence: 99%

“…Several EFPI-based configurations have been recently presented [21][22][23][24][25][26][27][28]; in addition, EFPI-based medical devices are commercially available [29]. It is possible to combine an EFPI probe with a fiber Bragg grating (FBG) [30,31], acting as temperature sensor in proximity of the EFPI sensor, to provide a dual sensing with cross compensation; such configuration has been proposed in [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

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Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments

et al. 2014

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We present a biocompatible, all-glass, 0.2 mm diameter, fiber-optic probe that combines an extrinsic Fabry-Perot interferometry and a proximal fiber Bragg grating sensor; the probe enables dual pressure and temperature measurement on an active 4 mm length, with 40 Pa and 0.2°C nominal accuracy. The sensing system has been applied to monitor online the radiofrequency thermal ablation of tumors in liver tissue. Preliminary experiments have been performed in a reference chamber with uniform heating; further experiments have been carried out on ex vivo porcine liver, which allowed the measurement of a steep temperature gradient and monitoring of the local pressure increase during the ablation procedure.

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Section: Sensor Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments

et al. 2014

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“…These advantages include immunity to electromagnetic interference, the capability of performing remote sensing, very high resolution, fast response, and compact size [1]. In general, such a pressure sensor based on a micro Fabry-Perot (FP) cavity commonly uses an elastic diaphragm attached at the tip of an optical fiber, and the diaphragm as one of the mirrors of the FP cavity can be made of various materials, such as silica [2], polymer [3], silver, and graphene [4,5]. The FP pressure sensors based on different diaphragms have been investigated intensively in recent years, and the sensitivity has been improved steadily.…”

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confidence: 99%

Fiber-optic acoustic pressure sensor based on large-area nanolayer silver diaghragm

et al. 2014

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A fiber-optic acoustic pressure sensor based on a large-area nanolayer silver diaphragm is demonstrated with a high dynamic pressure sensitivity of 160 nm∕Pa at 4 kHz frequency. The sensor exhibits a noise limited detectable pressure level of 14.5 μPa∕Hz 1∕2 . Its high dynamic pressure sensitivity and simple fabrication process make it an attractive tool for acoustic sensing and photo-acoustic spectroscopy. . Although the pressure sensitivity of the sensor based on the graphene diaphragm can potentially be very high thanks to small thickness, it is usually difficult to prepare and process single-or few-layered graphene diaphragms with large diameters and transfer them onto the sensor head. In addition, optical reflectivity of the graphene layer is relatively small compared to metal films. In this Letter, we demonstrate an acoustic sensor based on a large area silver diaphragm 150 nm in thickness and 2.4 mm in diameter. While the thickness is comparable to the graphite-based diaphragms previously reported [6], the diameter is an order of magnitude larger. The acoustic pressure test shows that such a sensor based on a large area silver diaphragm has a sensitivity of up to 160 nm∕Pa at 4 kHz frequency. To our best knowledge, this is the highest acoustic pressure sensitivity ever reported for fiber-optic acoustic sensors based on diaphragms. The sensor is able to detect acoustic pressure as weak as 14.5 μPa∕Hz 1∕2 . The acoustic pressure sensing head based on the silver diaphragm comprises a standard polarization maintaining fiber (PM fiber), a ceramic split sleeve, and the silver diaphragm, as shown in Fig. 1(a). Figure 1(b) is the image of the proposed sensing head. A picture of the ceramic split sleeve, on which the diaphragm is attached, is also shown in the bottom inset of Fig. 1(b), and the inner diameter of this split sleeve is 2.4 mm. The PM fiber end facet was polished with an angle of 8°to reduce the Fresnel reflection from the fiber end surface. The fabrication process of the sensing head is similar to that reported in our previous paper [5]. The distance between the fiber end and the diaphragm is approximately 150 μm adjusted by a high precision linear stage (Newport ILS-250CC) with a displacement resolution of 0.5 μm.The silver thin film used in this sensor is approximately 150 nm thick with >2.4 mm diameter that covers one end of the split sleeve. The top inset of Fig. 1(b) is an SEM image of the silver diaphragm. This sensing diaphragm has several advantages, including good stability and high reflectivity over the near infrared wavelength range. In general, the pressure sensitivity depends both on the material and the thickness of the diaphragm. In fact, the pressure sensitivity of an acoustic sensor based on an edge-clamped circular diaphragm is proportional to R 4 ∕t 3 , where R is the radius and t is the thickness of the diaphragm [7]. Therefore a diaphragm with large

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“…In medical applications, EFPI sensors operate in a small pressure range, usually 0-150 mmHg (0-20 kPa). Currently, the state-of-the-art EFPI sensors typically achieve an accuracy of 1 mmHg by using relatively simple interrogation approaches, with probes having a sensitivity > 1 nm/kPa [1][2][3][4].In this Letter, we introduce a novel algorithm for estimating the Fabry-Pérot cavity length, based on a white-light optical setup [5]. The algorithm can achieve a pressure accuracy of 6.1 Pa (0.045 mmHg), improving the normalised quadrature-point (QP) detection [6] by up to 6.4 times and requires no physical modification to the sensor.…”

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confidence: 99%

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confidence: 99%

Spectral eigendecomposition‐based algorithm for cavity estimation in fibre‐optic Fabry‐Pérot pressure sensors

et al. 2013

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A novel signal processing-based approach for the real-time estimation of air-gap length in fibre optic extrinsic Fabry-Pérot pressure sensors is presented; the algorithm is based on eigendecomposition of the spectrum mutual correlation matrix. A pressure accuracy of 6.1 Pa (0.045 mmHg) is achieved in a pressure probe with 1.13 nm/kPa sensitivity, highlighting a 6.4 times improvement over standard quadrature point amplitude tracking by just acting on signal processing.Introduction: Fibre-optic extrinsic Fabry-Pérot interferometry (EFPI)-based pressure sensors [1] are finding many emerging applications in medical devices [2], such as cardiovascular diagnosis of stenosis, intra-cranial pressure detection and intra-aortic balloon pumping [3]. In medical applications, EFPI sensors operate in a small pressure range, usually 0-150 mmHg (0-20 kPa). Currently, the state-of-the-art EFPI sensors typically achieve an accuracy of 1 mmHg by using relatively simple interrogation approaches, with probes having a sensitivity > 1 nm/kPa [1][2][3][4].In this Letter, we introduce a novel algorithm for estimating the Fabry-Pérot cavity length, based on a white-light optical setup [5]. The algorithm can achieve a pressure accuracy of 6.1 Pa (0.045 mmHg), improving the normalised quadrature-point (QP) detection [6] by up to 6.4 times and requires no physical modification to the sensor. The proposed algorithm makes use of the eigendecomposition of the mutual correlation, in the spectral domain, to provide a robust and reliable metric for online estimation of the Fabry-Pérot cavity length.

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High performance chitosan diaphragm-based fiber-optic acoustic sensor

Cited by 94 publications

References 13 publications

Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments

Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments

Fiber-optic acoustic pressure sensor based on large-area nanolayer silver diaghragm

Spectral eigendecomposition‐based algorithm for cavity estimation in fibre‐optic Fabry‐Pérot pressure sensors

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