Widefield optical coherence tomography by electro-optical modulation

Area of Science:

• Ophthalmology
• Biomedical Imaging
• Optical Engineering

Background:

• Optical coherence tomography (OCT) offers high-resolution, micron-level axial sectioning for various applications, including ophthalmology.
• Widefield retinal imaging is crucial for diagnosing retinal diseases, but fast OCT systems face depth-range limitations due to sample curvature and scan speed trade-offs.
• Current swept-source OCT technologies, while fast, struggle with limited depth range, hindering real-time imaging of curved biological tissues.

Purpose of the Study:

• To develop a method for extending the effective depth range of OCT systems for real-time imaging of highly curved samples.
• To enable widefield retinal imaging at high scan speeds without mechanical repositioning.
• To overcome the inherent trade-off between scan speed and depth range in OCT.

Main Methods:

• Utilized opto-electronic modulation of a single-frequency swept source laser.
• Implemented tailored numerical dispersion compensation techniques.
• Demonstrated harmonic image synthesis at any depth without mechanical sample manipulation.

Main Results:

• Achieved an 8-fold extension of the effective depth range for real-time imaging of highly curved samples.
• Successfully enabled widefield retinal imaging even at a 400 kHz swept source scan speed.
• Synthesized harmonic images at any depth, overcoming field-of-view restrictions.

Conclusions:

• Harmonic OCT effectively extends the depth range, enabling real-time widefield imaging of curved samples like the retina.
• The developed opto-electronic modulation and numerical compensation method overcomes limitations of current fast OCT systems.
• This advancement is significant for clinical ophthalmology and other fields requiring high-resolution imaging of curved surfaces.