Transparent capacitive micromachined ultrasound transducer linear arrays for combined realtime optical and ultrasonic imaging

Area of Science:

• Optics and Photonics
• Biomedical Engineering
• Materials Science

Background:

• Transparent ultrasound transducers are crucial for integrating optical and ultrasonic technologies.
• Previous work demonstrated transparent CMUTs for photoacoustic imaging.
• Combining real-time optical and ultrasonic imaging offers significant advantages for various applications.

Purpose of the Study:

• To investigate the feasibility of transparent CMUTs for simultaneous ultrasound and white-light imaging.
• To develop and characterize transparent CMUT arrays for multi-modal imaging applications.
• To demonstrate the potential of this technology for applications requiring co-registered optical and ultrasonic data.

Main Methods:

• Fabrication of transparent CMUT devices using adhesive wafer bonding.
• Characterization of optical transparency (up to 90%) and ultrasonic performance (9 MHz central frequency, 128 elements).
• Real-time plane-wave ultrasound imaging and through-array white-light imaging using a miniature camera.

Main Results:

• Achieved lateral and axial resolutions of 234 µm and 338 µm, respectively, for ultrasound imaging.
• Demonstrated high transmit sensitivity (1.4 kPa/V) and signal-to-noise ratio (28.4 dB) for transparent CMUTs.
• Successfully combined real-time ultrasound imaging with through-array white-light imaging using transparent arrays.

Conclusions:

• Transparent CMUT technology enables the first report of combined real-time optical and ultrasonic imaging with transparent arrays.
• This technology allows users to visually see what is being scanned and scan what is seen, eliminating co-registration errors.
• Potential future applications include multi-modality probes for interventional and surgical procedures, enhancing diagnostic and therapeutic capabilities.