Li Yong, Assouar M Badreddine
CNRS, Institut Jean Lamour, Vandoeuvre-lès-Nancy F-54500, France.
Université de Lorraine, Institut Jean Lamour, Boulevard des Aiguillettes, BP: 70239, Vandoeuvre-lès-Nancy 54506, France.
Sci Rep. 2015 Dec 1;5:17612. doi: 10.1038/srep17612.
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.
我们报道了利用无源超表面在非傍轴区域产生三维声学准直自加速光束。由四个亥姆霍兹谐振器和一根直管组成的混合结构构成的具有深亚波长空间分辨率的声学超表面，被证明能够高效地传输声音并完全改变局部相位。借助超表面提供的额外相位分布，透射声可以被调谐以沿任意焦散曲线传播，从而形成一个聚焦点。由于焦散特性，所形成的光束具有绕过障碍物和保持自愈合特性的能力，为波的操控开辟了一条新途径，并预示了各种潜在应用，特别是在超声成像、诊断和治疗领域。
