Depth of focus extension in optical coherence tomography using ultrahigh chromatic dispersion of zinc selenide.

We report a novel technique to overcome the depth-of-focus limitation in optical coherence tomography (OCT) using chromatic dispersion of zinc selenide lens. OCT is an established method of optical imaging, which found numerous biomedical applications. However, the depth scanning range of high-resolution OCT is limited by its depth of focus. Chromatic dispersion of zinc selenide lens allows to get high lateral resolution along extended depth of focus, because the different spectral components are focused at a different position along axes of light propagation. Test measurements with nanoparticle phantom show 2.8 times extension of the depth of focus compare to the system with a standard achromatic lens. The feasibility of biomedical applications was demonstrated by ex vivo imaging of the pig cornea and chicken fat tissue.