2D Au-Coated Resonant MEMS Scanner for NIR Fluorescence Intraoperative Confocal Microscope

Area of Science:

• Micro-electro-mechanical systems (MEMS)
• Optical imaging
• Biomedical engineering

Background:

• Microscopic imaging systems require miniaturization for intraoperative applications.
• Existing systems face limitations in form factor and scanning capabilities.
• Near-infrared (NIR) fluorescence imaging offers advantages for tissue visualization.

Purpose of the Study:

• To develop a novel 2D parametrically-resonant MEMS scanner for compact NIR intraoperative confocal microscopy.
• To achieve a large field-of-view (FOV) and high-speed imaging.
• To enable mass production with a high-yield microfabrication process.

Main Methods:

• Developed a 2D parametrically-resonant MEMS scanner with patterned gold coating for high reflectivity (>90% at 785 nm).
• Utilized a silicon-on-insulator (SOI) wafer-based, dicing-free microfabrication process.
• Integrated the MEMS scanner with a post-objective scanning architecture and piezoelectric actuator for axial scanning.

Main Results:

• Achieved a large mechanical scanning angle (MSA) of ±4° on each axis at a low driving voltage (36 V).
• Integrated the scanner into a 5.5 mm distal-end diameter NIR fluorescence intraoperative confocal microscope.
• Demonstrated ex vivo 2D imaging on human tissue specimens at up to five frames/s.

Conclusions:

• The developed 2D resonant MEMS scanner facilitates compact NIR intraoperative confocal microscopy.
• The scanner's design and fabrication process support mass production and high yield.
• Potential applications include multiphoton microendoscopy and wide-field endoscopy.