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Three-dimensional collimated self-accelerating beam through acoustic metascreen.

Li Y, Assouar MB - Sci Rep (2015)

Bottom Line: Acoustic metascreen with deep subwavelength spatial resolution, composed of hybrid structures combining four Helmholtz resonators and a straight pipe, transmitting sound efficiently and shifting fully the local phase is evidenced.With an extra phase profile provided by the metascreen, the transmitted sound can be tuned to propagate along arbitrary caustic curvatures to form a focused spot.Due to the caustic nature, the formed beam possesses the capacities of bypassing obstacles and holding the self-healing feature, paving then a new way for wave manipulations and indicating various potential applications, especially in the fields of ultrasonic imaging, diagnosis and treatment.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Institut Jean Lamour, Vandoeuvre-lès-Nancy F-54500, France.

ABSTRACT
We report the generation of three-dimensional acoustic collimated self-accelerating beam in non-paraxial region with sourceless metascreen. Acoustic metascreen with deep subwavelength spatial resolution, composed of hybrid structures combining four Helmholtz resonators and a straight pipe, transmitting sound efficiently and shifting fully the local phase is evidenced. With an extra phase profile provided by the metascreen, the transmitted sound can be tuned to propagate along arbitrary caustic curvatures to form a focused spot. Due to the caustic nature, the formed beam possesses the capacities of bypassing obstacles and holding the self-healing feature, paving then a new way for wave manipulations and indicating various potential applications, especially in the fields of ultrasonic imaging, diagnosis and treatment.

No MeSH data available.


Related in: MedlinePlus

Collimated self-bending beam from a point source.(a) The radiated sound field (normalized pressure field) from a point source located at (rs, zs) = (0, −10λ − h) and the transmitting one (normalized sound pressure level) through the metascreen with λ = 0.2 m. (b) Sound fields same to (a) while with a spherical obstacle in front of the metascreen and a ring-like obstacle along the trajectory. (c) Comparison of the SPL along the z axis in (a,b). The large deviation of the SPL around z = 0.5 m convincingly stems from the existing spherical obstacle.
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f4: Collimated self-bending beam from a point source.(a) The radiated sound field (normalized pressure field) from a point source located at (rs, zs) = (0, −10λ − h) and the transmitting one (normalized sound pressure level) through the metascreen with λ = 0.2 m. (b) Sound fields same to (a) while with a spherical obstacle in front of the metascreen and a ring-like obstacle along the trajectory. (c) Comparison of the SPL along the z axis in (a,b). The large deviation of the SPL around z = 0.5 m convincingly stems from the existing spherical obstacle.

Mentions: The realized collimated self-bending beam from the point source [cf. Fig. 4(a)] propagating along the designed trajectory closely resembles the desired beam illustrated in Fig. 3(a), providing a solid support for the great capacity of our presented screen. It is also not surprising to observe that the non-paraxial accelerating beam can convincingly bypass solid obstacle due to the curved trajectory and hold its own self-healing feature [cf. Fig. 4(b)]. A comparison of the SPL along the z direction for these cases [cf. Fig. 4(c)] indicates that, even if both obstacles block the formation of the desired wave field, the self-bending beam could be reconstructed to propagate along the desired trajectory and focused behind the solid obstacles.


Three-dimensional collimated self-accelerating beam through acoustic metascreen.

Li Y, Assouar MB - Sci Rep (2015)

Collimated self-bending beam from a point source.(a) The radiated sound field (normalized pressure field) from a point source located at (rs, zs) = (0, −10λ − h) and the transmitting one (normalized sound pressure level) through the metascreen with λ = 0.2 m. (b) Sound fields same to (a) while with a spherical obstacle in front of the metascreen and a ring-like obstacle along the trajectory. (c) Comparison of the SPL along the z axis in (a,b). The large deviation of the SPL around z = 0.5 m convincingly stems from the existing spherical obstacle.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664955&req=5

f4: Collimated self-bending beam from a point source.(a) The radiated sound field (normalized pressure field) from a point source located at (rs, zs) = (0, −10λ − h) and the transmitting one (normalized sound pressure level) through the metascreen with λ = 0.2 m. (b) Sound fields same to (a) while with a spherical obstacle in front of the metascreen and a ring-like obstacle along the trajectory. (c) Comparison of the SPL along the z axis in (a,b). The large deviation of the SPL around z = 0.5 m convincingly stems from the existing spherical obstacle.
Mentions: The realized collimated self-bending beam from the point source [cf. Fig. 4(a)] propagating along the designed trajectory closely resembles the desired beam illustrated in Fig. 3(a), providing a solid support for the great capacity of our presented screen. It is also not surprising to observe that the non-paraxial accelerating beam can convincingly bypass solid obstacle due to the curved trajectory and hold its own self-healing feature [cf. Fig. 4(b)]. A comparison of the SPL along the z direction for these cases [cf. Fig. 4(c)] indicates that, even if both obstacles block the formation of the desired wave field, the self-bending beam could be reconstructed to propagate along the desired trajectory and focused behind the solid obstacles.

Bottom Line: Acoustic metascreen with deep subwavelength spatial resolution, composed of hybrid structures combining four Helmholtz resonators and a straight pipe, transmitting sound efficiently and shifting fully the local phase is evidenced.With an extra phase profile provided by the metascreen, the transmitted sound can be tuned to propagate along arbitrary caustic curvatures to form a focused spot.Due to the caustic nature, the formed beam possesses the capacities of bypassing obstacles and holding the self-healing feature, paving then a new way for wave manipulations and indicating various potential applications, especially in the fields of ultrasonic imaging, diagnosis and treatment.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Institut Jean Lamour, Vandoeuvre-lès-Nancy F-54500, France.

ABSTRACT
We report the generation of three-dimensional acoustic collimated self-accelerating beam in non-paraxial region with sourceless metascreen. Acoustic metascreen with deep subwavelength spatial resolution, composed of hybrid structures combining four Helmholtz resonators and a straight pipe, transmitting sound efficiently and shifting fully the local phase is evidenced. With an extra phase profile provided by the metascreen, the transmitted sound can be tuned to propagate along arbitrary caustic curvatures to form a focused spot. Due to the caustic nature, the formed beam possesses the capacities of bypassing obstacles and holding the self-healing feature, paving then a new way for wave manipulations and indicating various potential applications, especially in the fields of ultrasonic imaging, diagnosis and treatment.

No MeSH data available.


Related in: MedlinePlus