Development and Characterization of a Superresolution Ultrasonic Transducer

Area of Science:

• Materials Science and Engineering
• Acoustics and Ultrasonics
• Biomedical Engineering

Background:

• High-sensitivity ultrasound probes are crucial for advancing biomedical ultrasound and industrial nondestructive testing (NDT).
• Improving imaging quality while maintaining low fabrication costs is a key trend in ultrasound system development.

Purpose of the Study:

• To develop and characterize an ultrasonic transducer capable of superfocusing ultrasonic waves beyond the diffraction limit.
• To achieve enhanced resolution for improved imaging in biomedical and NDT applications.

Main Methods:

• Additive manufacturing of the transducer case.
• Integration of a circular flat piezoelectric actuator and a core-shell lens (stainless steel core, polymer shell).
• Characterization of the transducer's focusing capabilities and imaging resolution at approximately 3 MHz.

Main Results:

• The transducer achieved superfocusing, with a beamwaist narrower than one wavelength.
• Transverse and axial resolutions of 0.65λ and 3λ/2 were obtained for C- and B-scan images, respectively.
• Successful imaging of subwavelength structures, including a Y-intersection of copper wire with hair-like diameter branches.

Conclusions:

• The developed ultrasonic transducer demonstrates significant potential for superresolution imaging.
• This technology represents a substantial advancement towards ultrasonic superresolution transducers for biomedical imaging and shallow NDT.
• The core-shell lens design is key to achieving the superfocusing effect.