Broadband single-phase hyperbolic elastic metamaterials for super-resolution imaging

Area of Science:

• Acoustics and Materials Science
• Wave Phenomena and Metamaterials

Background:

• Hyperbolic metamaterials offer advanced wave manipulation capabilities.
• Existing hyperbolic elastic metamaterials (HEMMs) have limitations in frequency width, scale adjustability, and imaging resolution due to empirical designs.

Purpose of the Study:

• To introduce an inverse-design strategy for HEMMs using topology optimization.
• To design broadband single-phase HEMMs capable of multipolar resonances at deep-subwavelength scales.
• To achieve super-resolution imaging for longitudinal waves.

Main Methods:

• Utilized topology optimization for inverse design of HEMMs.
• Designed broadband single-phase HEMMs supporting multipolar resonances.
• Demonstrated super-resolution imaging using optimized HEMMs.

Main Results:

• Achieved broadband operation and multipolar resonances at prescribed deep-subwavelength scales.
• Demonstrated super-resolution imaging for longitudinal waves.
• Attained a record imaging resolution of approximately λ/64 at ultra-low frequencies due to enhanced evanescent waves.

Conclusions:

• The inverse-design strategy provides a novel and general methodology for HEMM exploration.
• The developed HEMMs enable unprecedented imaging resolution, surpassing previous records in elastic metamaterials.
• This research guides advancements in ultrasonography and biomedical imaging applications.