Non-closed acoustic cloaking devices enabled by sequential-step linear coordinate transformations.

Area of Science:

• Acoustics
• Metamaterials
• Wave Manipulation

Background:

• Acoustic cloaking traditionally requires enclosing the object, limiting practical applications.
• Existing cloaking devices often depend on the specific characteristics of the object being concealed.

Purpose of the Study:

• To design and demonstrate a non-closed acoustic cloak capable of rendering arbitrary objects invisible.
• To develop a cloaking solution independent of the object's geometry and material properties.
• To explore applications in airborne and underwater acoustics.

Main Methods:

• Sequential linear coordinate transformations were applied to design a non-closed cloak with homogeneous materials.
• A non-closed carpet cloak was proposed for concealing objects on a reflecting plane.
• The concept was extended to a directional acoustic cloak for free-space applications.

Main Results:

• Numerical simulations confirmed the cloaking effect, demonstrating independence from the hidden object's characteristics.
• A non-resonant meta-atom was utilized to facilitate the physical realization of the proposed cloak.
• The design achieved an open invisible region, allowing for practical implementation.

Conclusions:

• The developed non-closed acoustic cloak offers a versatile solution for acoustic invisibility.
• The use of homogeneous materials and simple constitutive parameters simplifies realization.
• This work opens avenues for advanced acoustic devices in various fields, including sound manipulation and underwater acoustics.