Extended coherence length megahertz FDML and its application for anterior segment imaging

Area of Science:

• Biomedical Optics
• Ophthalmic Imaging
• Laser Technology

Background:

• Optical Coherence Tomography (OCT) is crucial for non-invasive imaging.
• High-speed and deep-field imaging are essential for detailed anterior segment analysis.
• Existing OCT systems face limitations in speed and imaging depth.

Purpose of the Study:

• To develop a 1300 nm Fourier Domain Mode Locked (FDML) laser for enhanced OCT.
• To achieve a high wavelength sweep rate (1.6 MHz) and ultra-long coherence length.
• To enable rapid volumetric deep field imaging of the human eye's anterior segment.

Main Methods:

• Designed and implemented a 1300 nm FDML laser system.
• Reduced dispersion in the fiber delay line to extend instantaneous coherence length.
• Characterized laser performance, including sweep rate and coherence length.
• Integrated the laser into an OCT system for anterior segment imaging.

Main Results:

• Achieved a 1.6 MHz wavelength sweep rate.
• Quadrupled the instantaneous coherence length compared to previous MHz-FDML setups.
• Increased imaging speed by a factor of 16 over previous extended coherence length results.
• Demonstrated the first MHz-OCT imaging of the human anterior segment.

Conclusions:

• The developed 1300 nm FDML laser significantly advances OCT capabilities.
• The system enables rapid, deep imaging of the entire anterior segment, from cornea to lens.
• This technology holds promise for improved ophthalmic diagnostics and research.