Spectral-domain optical coherence tomography with dual-balanced detection for auto-correlation artifacts reduction

Area of Science:

• Biomedical Optics
• Optical Imaging
• Medical Instrumentation

Background:

• Auto-correlation artifacts (AC) degrade the quality of optical coherence tomography (OCT) images.
• Existing OCT systems often struggle with effective artifact reduction, limiting diagnostic accuracy.
• Developing cost-effective solutions for artifact suppression is crucial for advancing OCT applications.

Purpose of the Study:

• To develop and validate a spectral domain optical coherence tomography (SD-OCT) system with dual-balanced detection (DBD) for reducing auto-correlation artifacts (AC).
• To enhance the signal-to-noise ratio (SNR) and overall image quality in OCT.
• To present a lower-cost alternative to existing dual-spectrometer designs.

Main Methods:

• Implementation of a free-space Michelson interferometer with a beam splitter introducing a π/2 phase shift.
• Simultaneous acquisition of two phase-opposed interferometric spectra using a three-line CCD.
• Utilizing dual-balanced detection (DBD) to cancel identical spectral components and suppress artifacts.

Main Results:

• Achieved approximately 9 dB reduction in auto-correlation artifacts (AC) and up to 30 dB suppression of the direct current (DC) term.
• Experimentally demonstrated a ~2.9 dB increase in signal-to-noise ratio (SNR).
• Validated artifact reduction efficacy on polymer coatings of drug-eluting stents and ex vivo swine corneal tissue.

Conclusions:

• The developed SD-OCT system with DBD effectively reduces AC and DC terms, significantly improving image quality.
• DBD offers inherent signal amplitude enhancement and a notable SNR increase.
• This cost-effective design presents a viable advancement for high-quality OCT imaging in biomedical applications.