Multimode fiber-optic hydrophone based on a schlieren technique

Spillman, William B.

doi:10.1364/ao.20.000465

Cited by 30 publications

(14 citation statements)

References 7 publications

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“…This work is supported by the NIH grant 5 RO1EB007117-02. In Intensity modulation acoustic sensors, information is encoded in the intensity of detected optical signal [9][10][11]. Both reflection as well as transmission type sensing schemes have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Broadband fiber optic hydrophone sensors for sub-millimeter ultrasound resolutions

Gopinath

Arora

Gandhi

et al. 2008

2008 International Topical Meeting on Microwave Photonics Jointly Held With the 2008 Asia-Pacific Microwave Photonics Conferenc

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Broadband fiber optic hydrophone probes are an attractive solution for characterization of ultrasound fields with sub-millimeter resolution up to 100MHz frequency range without need for complicated spatial averaging corrections. In this work, optical hydrophone sensors based on single mode straightcleaved fibers and down-tapered coated fibers with sensitive dimensions of less than 10μm have been reported. Thinly gold coated optical fiber sensors demonstrated a higher sensitivity and bandwidth performance than straight cleaved uncoated and down-tapered uncoated. The statistical analysis clearly indicates that the gold coated fibers with thickness of 30 nm provide a 26 dB improvement in sensitivity over that of the uncoated straight cleaved fibers, raising the overall sensitivity of the fiber optic hydrophone sensor to a value of -245 dB re 1V /μPa (unprecedented 0.56 V/ MPa). Broadband testing of these sensors with a 10MHz acoustic tone burst further indicates that the bandwidth of gold coated fiber sensor is as high as 60 MHz. Amplified optical source intensity noise limits the current intensity detection system up to 60MHz.

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Section: Introductionmentioning

confidence: 99%

Broadband fiber optic hydrophone sensors for sub-millimeter ultrasound resolutions

Gopinath

Arora

Gandhi

et al. 2008

2008 International Topical Meeting on Microwave Photonics Jointly Held With the 2008 Asia-Pacific Microwave Photonics Conferenc

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“…Spillman [29] and McMahon [28] also present a hydrophone based on Schlieren intensity modulation. Two Ronchi gratings (a standard diffraction grating, where ) are located perpendicular to the optical axis of two longitudinally separated fibers.…”

Section: Fiber Bragg Grating (Fbg)mentioning

confidence: 99%

Acousto-Ultrasonic Optical Fiber Sensors: Overview and State-of-the-Art

2008

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“…The transmitted light intensity thus varies in accordance with the pressure. A modification of the above approach is the schlieren technique [18], in which the region in between the two fibres is occupied by a grating structure to enhance system sensitivity by monitoring changes in coupling efficiency induced by diaphragm movement. A suitable sensitivity of these hydrophones is demonstrated for deep-sea applications over a frequency range of 100 Hz to 1 kHz.…”

Section: Transmission Typementioning

confidence: 99%

RF and Microwave Photonics in Biomedical Applications

Iezekiel

2009

Microwave Photonics

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In the last 20 years the field of microwave photonics has evolved due to unique features of analogue fibre-optic systems and its applications in radio over fibre for telecommunications [1] and optically controlled phased array antennas [2] for military applications, as has been discussed in earlier chapters of this book. Recently, microwave photonics techniques have also been extended to biomedical systems and this chapter presents two distinctive biomedical imaging applications that employ these techniques. (Optics already lends its application to laser Doppler anemometry, optical biopsy and optical molecular imaging, and phase microscopy.) The first application to be discussed is the design and implementation of optical hydrophone for calibration of ultrasound transducers for frequencies up to 100 MHz, which has found applications in sub-millimeter wave imaging and therapeutic applications. The second is the use of broadband modulated near infrared (NIR) light waves for quantifying blood flow and cellular functionality using spectroscopy, which is to be applied to coagulation monitoring and functional imaging with sub-centimetre spatial resolution using photon density waves. Both techniques are first discussed in terms of the fundamental physical interaction of lightwaves with biological tissues and the technical advantages that RF and microwave photonics could bring to conventional imaging modalities. Introduction to Optical HydrophoneOnly a decade ago, the highest ultrasound imaging frequency was of the order of 7 MHz. Today, modern diagnostic machines, particularly those designed for applications such as dermatology, ophthalmology and microsurgery, operate at centre frequencies close to 15 or 20 MHz [3].

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Multimode fiber-optic hydrophone based on a schlieren technique

Cited by 30 publications

References 7 publications

Broadband fiber optic hydrophone sensors for sub-millimeter ultrasound resolutions

Broadband fiber optic hydrophone sensors for sub-millimeter ultrasound resolutions

Acousto-Ultrasonic Optical Fiber Sensors: Overview and State-of-the-Art

RF and Microwave Photonics in Biomedical Applications

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