Acoustic Beam Scanning Using Annular Transducer Array Introducing Decentering Operation

Masuyama, Hiroyuki; Mizutani, Koichi

doi:10.1299/jsmec.49.681

Cited by 4 publications

(5 citation statements)

References 15 publications

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“…Acoustic Bessel beams have been excited using acoustical axicons [36], in analogy to the optical case. In any case, the most convenient way to form acoustic Bessel beams is by using annular transducer arrays [37,38]. The formation of an acoustic Bessel-like beam by using an axisymmetric grating of rigid tori was reported in [39].…”

Section: Introductionmentioning

confidence: 99%

Design of Acoustical Bessel-Like Beam Formation by a Pupil Masked Soret Zone Plate Lens

Tarrazó-Serrano

Castiñeira-Ibáñez

Minin

et al. 2019

Sensors

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The image performance of acoustic and ultrasound sensors depends on several fundamental parameters such as depth of focus or lateral resolution. There are currently two different types of acoustic diffractive lenses: those that form a diffraction-limited spot with a shallow depth of focus (zone plates) and lenses that form an extended focus (quasi-Bessel beams). In this paper, we investigate a pupil-masked Soret zone plate, which allows the tunability of a normalized angular spectrum. It is shown that the depth of focus and the lateral resolution can be modified, without changing the lens structure, by choosing the size of the pupil mask. This effect is based on the transformation of spherically-converging waves into quasi-conical waves, due to the apodization of the central part of the zone plate. The theoretical analysis is verified with both numerical simulations and experimental measurements. A Soret zone plate immersed in water with D/2F = 2.5 and F = 4.5λ changes its depth of focus from 2.84λ to 5.9λ and the lateral resolution increases from 0.81λ to 0.64λ at a frequency of 250 kHz, by modifying the pupil mask dimensions of the Soret zone plate.

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Section: Introductionmentioning

confidence: 99%

Design of Acoustical Bessel-Like Beam Formation by a Pupil Masked Soret Zone Plate Lens

Tarrazó-Serrano

Castiñeira-Ibáñez

Minin

et al. 2019

Sensors

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show abstract

“…For example, a flat acoustic lens with aperiodical structure to transform a divergent beam into a Bessel like beam was reported [27]. However, the most convenient way to form acoustic Bessel beams is by using annular transducer arrays [25,28]. Recently, the acoustic Bessel-like beam by means of an axisymmetric periodical grating of rigid tori was also reported [29], but it could be mentioned if Babinet's principle [30] is considered, both approaches (SZP and rigid tori scatterers) are considered equivalent.…”

Section: Introductionmentioning

confidence: 99%

Tunable depth of focus of acoustical pupil masked Soret Zone Plate

Castiñeira-Ibáñez

Tarrazó-Serrano

Minin

et al. 2019

Sensors and Actuators A: Physical

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In acoustical lenses both resolution and depth of focus are determined by diffraction and the smaller the lens aperture the worse the resolution and the greater the depth of focus. Diffraction-limited resolution has a Soret Zone Plate, but a long depth of focus has an axicon. Nevertheless, these are two different devices each of which requires its own independent design. In this paper we have shown that the transition from focusing to a diffraction limited spot to a quasi-diffraction free beam can be realized in the same focusing device without changing its topology. It has been shown that using a classical planar Soret Zone Plate lens made of a concentric array of circular aperiodical rings with an amplitude pupil mask placed closely to the surface of lens allows to form a quasi-Bessel beams under specific conditions, part of a diffracted wave collimates, producing an elongated focus. Experiments are performed in water tanks in order to verify the simulation results. Experimental verification shown that the depth of focus of a pupil-masked Soret Zone Plate increases 1.63 times and resolution increases 1.2 times (with minimal beam waist about of 0.67 of wavelength and depth of focus about 5.72 of wavelength). By dynamically controlling the size of the amplitude pupil mask, it is possible to quickly control the depth of focus of an acoustic lens.

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“…Acoustic Bessel beams have been excited using acoustical axicons [39], in analogy to the optical case. In any case, the most convenient way to form acoustic Bessel beams is by using annular transducer arrays [40,41]. The acoustic Bessel-like beam by means of an axisymmetric grating of rigid tori was reported in [42].…”

Section: Introductionmentioning

confidence: 99%

Design of Acoustical Bessel-Like Beam Formation by Tunable Angular Spectrum in Soret Zone Plate Lens

Tarrazó-Serrano¹,

Castiñeira-Ibáñez²,

Minin³

et al. 2018

Preprint

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The image performance of acoustic and ultrasound sensors depends on several fundamental parameters such as depth of focus or spatial resolution. There are currently two different type of acoustic diffractive lenses: those which form a diffraction-limited spot with a shallow depth of focus (zone plates) and lenses which form an extended focus (quasi-Bessel beams). In this paper, we investigate a pupil-masked Soret zone plate which allows the tunability of a normalized angular spectrum. It is shown that the depth of focus and the spatial resolution can be modified, without changing the lens structure, by choosing the size of the amplitude pupil mask. This effect is based on the transformation of spherically converging waves into quasi-conical waves, due to the apodization of the central part of the zone plate. The theoretical analysis is verified with both numerical simulations and experimental measurements. A Soret zone plate immersed in water with D/2F=2.5 and F=4.5$\lambda$, changes its depth of focus from 2.84$\lambda$ to 5.9$\lambda$ and the spatial resolution increases from 0.81$\lambda$ to 0.64$\lambda$ at a frequency of 250 kHz, by modifying the pupil mask dimensions of the Soret zone plate.

show abstract

Acoustic Beam Scanning Using Annular Transducer Array Introducing Decentering Operation

Cited by 4 publications

References 15 publications

Design of Acoustical Bessel-Like Beam Formation by a Pupil Masked Soret Zone Plate Lens

Design of Acoustical Bessel-Like Beam Formation by a Pupil Masked Soret Zone Plate Lens

Tunable depth of focus of acoustical pupil masked Soret Zone Plate

Design of Acoustical Bessel-Like Beam Formation by Tunable Angular Spectrum in Soret Zone Plate Lens

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