Amorphous silicon-carbide photonics for ultrasound imaging

Area of Science:

• Photonics
• Materials Science
• Biomedical Engineering

Background:

• Photonic ultrasound sensors offer superior resolution and sensitivity compared to conventional methods.
• Challenges remain in achieving miniaturization, high sensitivity, and broad bandwidth simultaneously.
• Optical materials can enhance sensor performance and stability.

Purpose of the Study:

• To introduce amorphous silicon carbide (a-SiC) as a novel material for miniaturized photonic ultrasound sensors.
• To demonstrate the performance of a-SiC microring sensors in terms of sensitivity, bandwidth, and noise-equivalent pressure.
• To validate the real-world applicability of a-SiC sensors for high-resolution ultrasound imaging.

Main Methods:

• Fabrication of miniaturized microring sensors using amorphous silicon carbide (a-SiC).
• Development of a compact detection system with a 20-transducer linear array coupled to a single bus waveguide.
• Characterization of sensor performance, including optical finesse, intrinsic sensitivity, and noise-equivalent pressure across a wide frequency range.

Main Results:

• Achieved an optical finesse of 1320 and intrinsic sensitivity of 78 fm/kPa.
• Demonstrated a noise-equivalent pressure below 55 mPa/√Hz, calibrated from 3.36 MHz to 30 MHz.
• Validated high-resolution imaging of fine structures, confirming practical applicability.
• a-SiC's low deposition temperature facilitates integration on various substrates.

Conclusions:

• Amorphous silicon carbide (a-SiC) is a promising material for advanced optical ultrasound sensing.
• a-SiC enables the development of highly sensitive, miniaturized sensors with broad bandwidth.
• This technology holds potential for next-generation ultrasound imaging systems.