Time reversal imaging of complex sources in a three-dimensional environment using a spatial inverse filter

Area of Science:

• Acoustics
• Wave physics
• Metamaterials

Background:

• Time reversal focusing is a technique used to concentrate acoustic waves.
• Previous studies focused on coplanar arrays and direct sound emissions.
• The impact of reverberation on focusing quality was not fully explored.

Purpose of the Study:

• To investigate time reversal focusing using a 2D resonator array in a reverberant environment.
• To explore the generation of subwavelength focal features and complex source imaging.
• To assess the robustness of focusing quality with oblique wave incidence.

Main Methods:

• Utilizing a two-dimensional array of resonators in a reverberation chamber.
• Recording the full impulse response of acoustic wave propagation.
• Applying a spatial inverse filter to achieve acoustic focusing and image complex sources.

Main Results:

• Demonstrated subwavelength focusing capabilities of the resonator array.
• Successfully generated focal images of complex sources like dipoles and quadrupoles.
• Achieved high-fidelity super-resolution imaging despite reverberation and oblique wave incidence.

Conclusions:

• Time reversal focusing with resonator arrays is effective in complex, reverberant environments.
• The method enables the creation of subwavelength features and detailed imaging of acoustic sources.
• This technique offers a robust approach for advanced acoustic manipulation and imaging.