Laser-generated MHz elastic waves from metallic-liquid interfaces

Gutfeld, R. J. von; Budd, H. F.

doi:10.1063/1.90637

Cited by 48 publications

(18 citation statements)

References 5 publications

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“…For ultrasonic generation, as shown in Fig. 1(d), a section of the fiber cladding before the TFBG is partially removed and replaced with laser-responsive, ultrasonic-generating materials, such as metal films [11], polymer composite [12], gold nanoparticles arrays [13], and carbon nanotube composite [14]. Because the core mode is well confined at the center of the fiber while the ghost mode spread out to the whole cross-section of the fiber, as shown in Fig.…”

Section: Principle Of Operationmentioning

confidence: 99%

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

Tian¹,

Zhang²,

Han³

2013

Opt. Express

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Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiberoptic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasidistributed biochemical fiber-optic sensing. 1175-1179 (1985).

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Section: Principle Of Operationmentioning

confidence: 99%

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

Tian¹,

Zhang²,

Han³

2013

Opt. Express

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“…Typically, such transmitters are made of light-absorbing thin films containing specific structures designed to have high optical absorption that are capable of efficient optoacoustic conversion, for example, thin metal, 1 dye-doped polymer composites, 2,3 and two-dimensional ͑2D͒ gold nanoparticle ͑AuNP͒ arrays. 4 They are often integrated with optical interferometric detectors ͑e.g., FabryPérot etalon͒ 5 to make all-optical ultrasound transducers working over broadband and high frequency in 2D array platforms.…”

mentioning

confidence: 99%

Carbon nanotube composite optoacoustic transmitters for strong and high frequency ultrasound generation

Baac

Ling

et al. 2010

Applied Physics Letters

151

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We demonstrate carbon nanotube ͑CNT͒ composite-based optoacoustic transmitters that generate strong and high frequency ultrasound. The composite consists of CNTs grown on a substrate, which are embedded in elastomeric polymer used as an acoustic transfer medium. Under pulsed laser excitation, the composite generates very strong optoacoustic pressure: 18 times stronger than a Cr film reference and five times stronger than a gold nanoparticle composite with the same polymer. This enhancement persists over a broadband frequency range of up to 120 MHz and is confirmed by calculation. We suggest the CNT-polymer composites as highly efficient optoacoustic transmitters for high resolution ultrasound imaging. © 2010 American Institute of Physics. ͓doi:10.1063/1.3522833͔Laser-induced ultrasound generation is an effective way to make high frequency ultrasound transmitters by exploiting the high frequency spectra of laser pulses to achieve broad acoustic bandwidths. Typically, such transmitters are made of light-absorbing thin films containing specific structures designed to have high optical absorption that are capable of efficient optoacoustic conversion, for example, thin metal, 1 dye-doped polymer composites, 2,3 and two-dimensional ͑2D͒ gold nanoparticle ͑AuNP͒ arrays. 4 They are often integrated with optical interferometric detectors ͑e.g., FabryPérot etalon͒ 5 to make all-optical ultrasound transducers working over broadband and high frequency in 2D array platforms. In these arrays, the size of each element was determined by the spot size of the focused laser beam that is of the order of several microns.Thin metallic coatings on solid substrates are suitable as a common reference material for qualifying the performance of optoacoustic transmitters.1,2 While these thin films ͑Ͻ1 m͒ can be used as high frequency ultrasound sources their optoacoustic conversion efficiency is poor mainly because of the low thermal expansion. Also, a significant percentage of light is reflected back from the film surface.As large thermal expansion is desirable for strong pressure generation, an elastomeric polymer, polydimethylsiloxane ͑PDMS͒, has been used as an acoustic transfer medium to interface with light-absorbers.2-5 A composite film of PDMS with carbon black as a light-absorber has shown nearly 20 dB improvement in optoacoustic signal strength as compared to a reference Cr film alone.2 However, high frequency response was severely limited due to the composite film thickness ͑ϳ25 m͒ due to the acoustic attenuation. This is a serious issue because high frequency performance is vital for optoacoustic transmitters. Moreover, it is challenging to obtain uniform mixing and dispersion of carbon black particles in the PDMS matrix. Agglomeration of carbon black can cause uneven light absorption within the same film. Significant progress has been recently made using a planar array of AuNPs with an overlying PDMS layer of several microns. 4 High frequency output was improved by ϳ5 dB over 70-100 MHz as compared with those carbon black-PDMS...

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“…따라서 오래 전부터 산모와 태아를 진단하는 데 널리 사용되고 있으 며 근래에는 일반 환자의 체내 근육, 힘줄, 장기들의 크기와 구조들을 단층영상으로 가시화하는데 사용되고 있다 [3] . [4] , 금속 미세패턴 (Au nanoparticle) [5] 또는 CNT (carbon nanotube)를 PDMS (Polydimethylsiloxane)와 혼합하는 방법에 기반하고 있다 [6][7][8][9] . …”

Section: 서 론unclassified

Optoacoustic Ultrasound Generator Based on Nanostructured Germanium

Yoon¹,

Heo

2015

Korean Journal of Optics and Photonics

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We have fabricated an optoacoustic ultrasound generator based on nanostructured germanium (Ge). Ge thin films were deposited via e-beam evaporation and then etched using a metal-assisted chemical (MAC) method to form nanostructured Ge films. The measured intensity of ultrasound from the nanostructured Ge covered with PDMS was about 3 times stronger than that of 100-nm-thick chromium (Cr). When the nanostructured Ge was embedded in the PDMS, the intensity of ultrasound became 8.5 times as strong compared to the 100-nm-thick Cr.

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Laser-generated MHz elastic waves from metallic-liquid interfaces

Cited by 48 publications

References 5 publications

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

Carbon nanotube composite optoacoustic transmitters for strong and high frequency ultrasound generation

Optoacoustic Ultrasound Generator Based on Nanostructured Germanium

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