Coaxial Bright and Dark Field Optical Coherence Tomography

Area of Science:

• Biomedical Optics
• Medical Imaging Technology

Background:

• Optical Coherence Tomography (OCT) is a key imaging modality in biomedical research.
• Improving signal collection efficiency and image quality in OCT remains a critical challenge.

Purpose of the Study:

• To develop a novel OCT system with enhanced signal collection efficiency and improved image characteristics.
• To enable simultaneous acquisition of bright-field and dark-field OCT signals.

Main Methods:

• Implementation of a coaxial optical design featuring a wavefront-division beam splitter and a 45-degree rod mirror.
• Simultaneous detection of bright-field (standard OCT) and dark-field signals using a single spectrometer and fiber array.
• Compounding of bright and dark field images to reduce speckle noise.

Main Results:

• Achieved approximately 3 dB improvement in signal collection efficiency for biological tissues.
• Dark-field OCT imaging demonstrated higher resolution, contrast, and distinct information compared to bright-field OCT.
• Speckle noise was suppressed by approximately √2 when compounding both signal types.

Conclusions:

• The novel coaxial OCT design significantly enhances signal collection efficiency and image quality.
• This advancement offers improved depth, contrast, resolution, speckle reduction, and signal-to-noise ratio for OCT.
• The technology holds great potential for comprehensive tissue characterization and broader clinical/biomedical applications.