Swept source optical coherence microscopy using a 1310 nm VCSEL light source.

Area of Science:

• Biomedical Optics
• Microscopy Technology
• Medical Imaging

Background:

• Optical Coherence Microscopy (OCM) offers high-resolution cross-sectional imaging.
• Swept-source OCM requires fast, tunable laser sources for efficient data acquisition.
• Existing OCM systems may have limitations in speed, resolution, or flexibility.

Purpose of the Study:

• To demonstrate a high-speed swept-source OCM system.
• To utilize a MEMS-tunable vertical cavity surface-emitting laser (VCSEL) as the light source.
• To evaluate the system's performance in imaging biological tissues.

Main Methods:

• Employed a MEMS-tunable VCSEL with a 280 kHz sweep rate for bidirectional axial scanning at 560 kHz.
• Achieved an axial resolution of 8.1 µm in tissue using a 117 nm bandwidth centered at 1310 nm.
• Implemented numerical dispersion mismatch compensation and path length correction for enhanced image quality and flexibility.
• Acquired images with transverse resolutions from 0.86 µm to 3.42 µm and fields of view up to ~2 mm x 2 mm.
• Generated large field-of-view mosaics from serially acquired overlapping microscopic fields.

Main Results:

• Demonstrated high-speed OCM imaging with a 560 kHz bidirectional axial scan rate.
• Achieved high transverse and axial resolutions suitable for microscopic tissue analysis.
• Successfully imaged fresh human colon, thyroid, and kidney specimens ex vivo.
• Validated OCM image accuracy by comparison with corresponding histology sections.

Conclusions:

• The developed swept-source OCM system provides high-speed, high-resolution imaging capabilities.
• The system's flexibility in magnification and field of view facilitates integration with various microscopy setups.
• OCM is a viable technique for detailed ex vivo imaging and analysis of biological tissue specimens.