High-speed, high resolution OCT imaging of the retina with frequency swept lasers at 850 nm

Ophthalmie OCT was performed using a novel, compact external cavity semiconductor laser at ∼850 nm. Retinal imaging was demonstrated with a resolution of <7 microns in tissue at a speed of 16,000 axial scans per second. The coherence length of the laser is >10 mm, enabling an axial measurement range of ∼2.5 mm. Real-time display and data streaming capabilities enable video-rate imaging of the retina at >30 frames per second. High-definition and three-dimensional imaging were demonstrated on normal retinas. The resolution of <7 microns in the retina is, to our knowledge, the highest resolution achieved in the retina with swept source OCT to date. The long coherence length of the laser enables high-sensitivity measurements over a large axial measurement range. The speed of 16,000 axial scans per second is comparable to current spectrometer-based spectral/Fourier domain OCT systems. The low cost and small footprint of our laser (∼10 cm × 20 cm) may enable the development of OCT for novel applications. Further improvements in speed will be possible by using alternative scanning methods.