High resolution optical coherence tomography with an improved depth range using an axicon lens

摘要

In optical coherence tomography (OCT), Axial and lateral resolutions are determined by the source coherence length and numerical aperture of the sampling lens, respectively. While axial resolution can be improved using a broadband light source, there is a trade-off between lateral resolution and focusing depth when conventional optical elements are used. The incorporation of an axicon lens into the sample arm of the interferometer overcomes this limitation. Using an axicon lens with a top angle of 160 degrees, 10 &mgr;m or better-lateral resolution is maintained over a focusing depth of at least 6 mm. In addition to high lateral resolution, the focusing spot intensity is approximately constant over a greater depth range.