Computational framework for combining multiple swept-sources for high-resolution in-vivo optical coherence...

Area of Science:

• Biomedical Optics
• Optical Imaging
• Medical Technology

Background:

• Axial resolution in swept-source Fourier-domain optical coherence tomography (FD-OCT) is fundamentally limited by the laser's sweep range.
• Achieving broad sweep ranges is challenging, and combining multiple laser sources passively is complex.

Purpose of the Study:

• To develop a computational framework for enhancing axial resolution in full-field FD-OCT (FF-FD-OCT) by combining independently sweeping laser sources.
• To overcome the limitations of single-source sweep range in achieving high-resolution OCT imaging.

Main Methods:

• Developed a dual-laser FF-FD-OCT system using sequentially sweeping lasers.
• Implemented a post-processing technique to phase-correctly stitch spectra from individual lasers, creating a high-bandwidth spectrum.
• Utilized a one-time calibration for non-linear sweeps and wavelength overlap, plus volume-by-volume phase matching for motion compensation.

Main Results:

• Achieved an effective bandwidth of 145 nm at a central wavelength of 878 nm.
• Attained a high axial resolution of 3.1 μm.
• Demonstrated system operation at an A-scan rate of 50 MHz, validated with ex-vivo phantoms and in-vivo retinal data.

Conclusions:

• The computational framework successfully enhances axial resolution in FF-FD-OCT by combining multiple laser sources.
• The method is adaptable and can be extended to more lasers for further resolution improvements.
• This approach offers a viable path to higher resolution OCT imaging for various applications.