Fourier domain optical coherence tomography with an 800-μm diameter axicon lens for long-depth-range probing

Recently, Fourier domain optical coherence tomography (FDOCT) has attracted much attention due to the significantly improved sensitivity and imaging speed compared to time domain OCT. The large depth of focus is necessary to image a long-depth-range sample with constant transverse resolution in FDOCT where dynamic focusing is not considered. Under such imaging scheme, an axicon lens can be used instead of a conventional focusing lens in the sample arm of OCT to achieve both high lateral resolution and a long depth of focus simultaneously. In this study, a 800μm diameter axicon lens was fabricated on a silica wafer. We incorporated the fabricated axicon lens into the sample arm of our FD OCT system and investigated the lateral resolution over a long depth range, compared to the same FD OCT system using a conventional lens.