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Manipulation of acoustic focusing with an active and configurable planar metasurface transducer.

Zhao J, Ye H, Huang K, Chen ZN, Li B, Qiu CW - Sci Rep (2014)

Bottom Line: It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area.Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns.Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Republic of Singapore [2] Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore.

ABSTRACT
It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area. However, previous researches seldom consider the focal resolution, whose focal size is much larger than one wavelength. Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns. Here, an active and configurable planar metasurface PT prototype is proposed to manipulate the acoustic focal pattern and the focal resolution freely. By suitably optimized ring configurations of the active metasurface PT, we demonstrate the manipulation of focal patterns in acoustic far fields, such as the designed focal needle and multi foci. Our method is also able to manipulate and improve the cross-sectional focal resolution from subwavelength to the extreme case: the deep sub-diffraction-limit resolution. Via the acoustic Rayleigh-Sommerfeld diffraction integral (RSI) cum the binary particle swarm optimization (BPSO), the free manipulation of focusing properties is achieved in acoustics for the first time. Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.

No MeSH data available.


Related in: MedlinePlus

(a) Schematics of the configurable planar metasurface PT prototype. Inside the dashed box is the radial cross-sectional view of the ring configuration, showing the unevenly-distributed piezoelectric elements and the hard boundaries. (b) The B.C.s of each piezoelectric ring observed from the radial cross-sectional view.
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f1: (a) Schematics of the configurable planar metasurface PT prototype. Inside the dashed box is the radial cross-sectional view of the ring configuration, showing the unevenly-distributed piezoelectric elements and the hard boundaries. (b) The B.C.s of each piezoelectric ring observed from the radial cross-sectional view.

Mentions: In the three-dimensional view of the configurable planar metasurface PT prototype in Fig. 1(a), piezoelectric rings (red) are unevenly spaced with hard-boundary mask rings (blue) in between. A type of common artificial ceramic is employed as the piezoelectric material: lead zirconate titanate PZT-5H16. In the radial view, the thickness q is set identical for all PZT-5H rings, and the ring configuration (r1, rr1, r2, rr2 …) will be optimized according to different focusing manipulation. The thin hard-boundary mask rings in between, through which no sound can pass, are the complements of the spaced gaps between PZT-5H rings, co-planar with z = 0. The entire PT is axisymmetric with respect to +z, and the upper surface of the structure at z = 0 can be regarded as a flat active metasurface according to the radial cross-sectional view. In our following demonstrations in air (density: ρ0 = 1.21 kg/m3; speed of sound: c0 = 343 m/s), we will show the designed focal pattern and the focal resolution created with the PT prototype in acoustic far fields, the simulation of which is carried out by the finite element method (FEM). In detail, COMSOL Multiphysics is the platform we use, and the simulation is facilitated by the coupling of the embedded acoustic module and the acoustic-piezoelectric interaction module concurrently.


Manipulation of acoustic focusing with an active and configurable planar metasurface transducer.

Zhao J, Ye H, Huang K, Chen ZN, Li B, Qiu CW - Sci Rep (2014)

(a) Schematics of the configurable planar metasurface PT prototype. Inside the dashed box is the radial cross-sectional view of the ring configuration, showing the unevenly-distributed piezoelectric elements and the hard boundaries. (b) The B.C.s of each piezoelectric ring observed from the radial cross-sectional view.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150112&req=5

f1: (a) Schematics of the configurable planar metasurface PT prototype. Inside the dashed box is the radial cross-sectional view of the ring configuration, showing the unevenly-distributed piezoelectric elements and the hard boundaries. (b) The B.C.s of each piezoelectric ring observed from the radial cross-sectional view.
Mentions: In the three-dimensional view of the configurable planar metasurface PT prototype in Fig. 1(a), piezoelectric rings (red) are unevenly spaced with hard-boundary mask rings (blue) in between. A type of common artificial ceramic is employed as the piezoelectric material: lead zirconate titanate PZT-5H16. In the radial view, the thickness q is set identical for all PZT-5H rings, and the ring configuration (r1, rr1, r2, rr2 …) will be optimized according to different focusing manipulation. The thin hard-boundary mask rings in between, through which no sound can pass, are the complements of the spaced gaps between PZT-5H rings, co-planar with z = 0. The entire PT is axisymmetric with respect to +z, and the upper surface of the structure at z = 0 can be regarded as a flat active metasurface according to the radial cross-sectional view. In our following demonstrations in air (density: ρ0 = 1.21 kg/m3; speed of sound: c0 = 343 m/s), we will show the designed focal pattern and the focal resolution created with the PT prototype in acoustic far fields, the simulation of which is carried out by the finite element method (FEM). In detail, COMSOL Multiphysics is the platform we use, and the simulation is facilitated by the coupling of the embedded acoustic module and the acoustic-piezoelectric interaction module concurrently.

Bottom Line: It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area.Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns.Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Republic of Singapore [2] Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore.

ABSTRACT
It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area. However, previous researches seldom consider the focal resolution, whose focal size is much larger than one wavelength. Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns. Here, an active and configurable planar metasurface PT prototype is proposed to manipulate the acoustic focal pattern and the focal resolution freely. By suitably optimized ring configurations of the active metasurface PT, we demonstrate the manipulation of focal patterns in acoustic far fields, such as the designed focal needle and multi foci. Our method is also able to manipulate and improve the cross-sectional focal resolution from subwavelength to the extreme case: the deep sub-diffraction-limit resolution. Via the acoustic Rayleigh-Sommerfeld diffraction integral (RSI) cum the binary particle swarm optimization (BPSO), the free manipulation of focusing properties is achieved in acoustics for the first time. Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.

No MeSH data available.


Related in: MedlinePlus