Polarization-insensitive optical coherence tomography using pseudo-depolarized reference light for mitigating...

Area of Science:

• Biomedical Optics
• Optical Engineering

Background:

• Optical coherence tomography (OCT) is susceptible to image artifacts caused by sample or system birefringence when using polarized light.
• These artifacts compromise image quality and diagnostic accuracy in OCT.

Purpose of the Study:

• To mitigate birefringence-related artifacts in OCT images.
• To enhance image quality and diagnostic information in OCT.

Main Methods:

• Investigated liquid crystal patterned retarders as pseudo-depolarizers in the reference arm of OCT systems.
• Evaluated configurations in spectral-domain OCT using Michelson and Mach-Zehnder interferometers.
• Tested performance with an achromatic quarter-wave plate to control sample polarization states.

Main Results:

• The optimal depolarizer configuration significantly reduced cross-polarization artifacts by 3.9 dB (Michelson) and 7.0 dB (Mach-Zehnder).
• Demonstrated substantial improvement in OCT signal magnitude and image quality in biological samples (marmot eye, mouse tail).
• Achieved drastic elimination of birefringence-related artifacts, enhancing detected signal intensity.

Conclusions:

• Presents a simple, cost-effective technique to mitigate OCT birefringence artifacts.
• The method is readily implementable in existing OCT systems.
• Improves the effectiveness of OCT imaging across various biomedical applications.