Large-field-of-view optical-resolution optoacoustic microscopy using a stationary silicon-photonics acoustic detector

Area of Science:

• Biomedical Optics
• Medical Imaging
• Acoustic Sensing

Background:

• Optical-resolution optoacoustic microscopy (OR-OAM) offers label-free microvasculature imaging.
• Current OR-OAM systems often require bulky coaxial setups with mechanical scanning of ultrasound transducers, limiting field of view and portability.
• A key challenge is developing OR-OAM configurations that eliminate the need for physical scanning of acoustic components.

Purpose of the Study:

• To develop an OR-OAM system that bypasses the need for physically scanning the ultrasound transducer or acoustic beam path.
• To demonstrate a non-coaxial OR-OAM configuration for efficient microvasculature imaging.

Main Methods:

• A novel OR-OAM system utilizing a silicon-photonics acoustic detector (SPADE) with semi-isotropic sensitivity was developed.
• The system employed a non-coaxial configuration where only the optical excitation beam was scanned, while the SPADE remained stationary.
• Demonstrations were performed in both epi-illumination and trans-illumination configurations.

Main Results:

• The system achieved imaging of resolution targets and in vivo microvasculature in a mouse ear.
• Demonstrated optoacoustic imaging with focal spots down to sub-micron levels and lateral resolution of $$.
• Achieved a field of view exceeding 4 mm in both lateral dimensions without acoustic scanning.

Conclusions:

• A new OR-OAM design compatible with epi-illumination was successfully showcased.
• The developed setup enables large fields of view without scanning acoustic components, offering potential for high-speed imaging.
• This compact, miniature probe design could significantly facilitate the clinical translation of OR-OAM technology.