Limits...
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

Illustration of a three-dimensional collimated self-accelerating beam.(a) The metascreen (black line) in a cylindrical coordinate can provide a local phase shift profile ϕ(r) on an incident wave to transmit sound propagating along a curved trajectory r = f(z) (blue line) and focusing at a spot (red dot). For the demonstration the capacities of the metascreen, a spherical and a ring-like solid obstacle (three yellow circles in the r − z plane) are placed in front of the metascreen and along the trajectory to block the formation of the focused beam. (b) The required phase shift profile provided by the metascreen to form a self-accelerating beam propagating along a circular trajectory with diameter of 2.5λ. The phase curve covering 2π range varied rapidly along the r direction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4664955&req=5

f1: Illustration of a three-dimensional collimated self-accelerating beam.(a) The metascreen (black line) in a cylindrical coordinate can provide a local phase shift profile ϕ(r) on an incident wave to transmit sound propagating along a curved trajectory r = f(z) (blue line) and focusing at a spot (red dot). For the demonstration the capacities of the metascreen, a spherical and a ring-like solid obstacle (three yellow circles in the r − z plane) are placed in front of the metascreen and along the trajectory to block the formation of the focused beam. (b) The required phase shift profile provided by the metascreen to form a self-accelerating beam propagating along a circular trajectory with diameter of 2.5λ. The phase curve covering 2π range varied rapidly along the r direction.

Mentions: The desired three-dimensional acoustic collimated self-accelerating beam in non-paraxial domain is illustrated in Fig. 1(a). The metascreen possess the abilities of providing a local phase shift ϕ(r) on the incident sound field, consequently shaping the transmitted sound propagating along a desired trajectory r = f(z), and finally forming a focusing spot at a the intersectional region of the trajectory. The relationship between the phase shift profile and the desired trajectory could be retrieved from tracing each individual caustic ray and expressed as111227


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

Li Y, Assouar MB - Sci Rep (2015)

Illustration of a three-dimensional collimated self-accelerating beam.(a) The metascreen (black line) in a cylindrical coordinate can provide a local phase shift profile ϕ(r) on an incident wave to transmit sound propagating along a curved trajectory r = f(z) (blue line) and focusing at a spot (red dot). For the demonstration the capacities of the metascreen, a spherical and a ring-like solid obstacle (three yellow circles in the r − z plane) are placed in front of the metascreen and along the trajectory to block the formation of the focused beam. (b) The required phase shift profile provided by the metascreen to form a self-accelerating beam propagating along a circular trajectory with diameter of 2.5λ. The phase curve covering 2π range varied rapidly along the r direction.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Illustration of a three-dimensional collimated self-accelerating beam.(a) The metascreen (black line) in a cylindrical coordinate can provide a local phase shift profile ϕ(r) on an incident wave to transmit sound propagating along a curved trajectory r = f(z) (blue line) and focusing at a spot (red dot). For the demonstration the capacities of the metascreen, a spherical and a ring-like solid obstacle (three yellow circles in the r − z plane) are placed in front of the metascreen and along the trajectory to block the formation of the focused beam. (b) The required phase shift profile provided by the metascreen to form a self-accelerating beam propagating along a circular trajectory with diameter of 2.5λ. The phase curve covering 2π range varied rapidly along the r direction.
Mentions: The desired three-dimensional acoustic collimated self-accelerating beam in non-paraxial domain is illustrated in Fig. 1(a). The metascreen possess the abilities of providing a local phase shift ϕ(r) on the incident sound field, consequently shaping the transmitted sound propagating along a desired trajectory r = f(z), and finally forming a focusing spot at a the intersectional region of the trajectory. The relationship between the phase shift profile and the desired trajectory could be retrieved from tracing each individual caustic ray and expressed as111227

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