Phase-referenced Doppler optical coherence tomography in scattering media

Area of Science:

• Optical Engineering
• Biomedical Optics
• Interferometry

Background:

• Phase noise is a significant limitation in low-coherence interferometry.
• Doppler Optical Coherence Tomography (OCT) systems are sensitive to velocity noise.
• Existing methods for noise reduction in OCT are often complex or not real-time compatible.

Purpose of the Study:

• To develop a fiber-based interferometer with reduced phase noise.
• To integrate this interferometer into a Doppler OCT system for velocity noise reduction.
• To demonstrate the effectiveness of the system in reducing velocity noise in various samples.

Main Methods:

• A fiber-based, low-coherence interferometer was designed and implemented.
• A second, narrowband, continuous-wave light source was used as a phase reference.
• The interferometer was integrated into a Doppler OCT system, and processing techniques amenable to real-time implementation were employed.

Main Results:

• The novel interferometer significantly reduced phase noise.
• Significant velocity noise reduction was demonstrated in both reflective and scattering samples.
• A 90% suppression of velocity noise was achieved in a flow phantom using the developed system.

Conclusions:

• The proposed fiber-based interferometer effectively reduces phase noise.
• Integration into Doppler OCT systems leads to substantial velocity noise reduction.
• The demonstrated noise suppression is compatible with real-time processing and has potential for advanced OCT applications.