DMD-based structured illumination full-field optical coherence tomography

Full field optical coherence tomography (FF-OCT) utilizes low coherence gate to suppress the out-of-focus scattering light. The spatial resolution remains limited by numerical aperture of objective and bandwidth of light source. Structured illumination microscopy not only is a wide-field three-dimensional imaging modality which shift high spatial frequency components to optical transfer function of system, but also enables optical sectioning in biological tissue. Thus, we propose a structured illumination based FF-OCT(SI-FF-OCT) to realize three-dimensional sub-cellular resolution using parallel coded digital micromirror device (DMD). First, the principle of SI-FF-OCT was introduced in terms of point spread function (PSF) of the standard FF-OCT optical system. Second, a 1D illumination pattern of SI-FF-OCT for imaging random tissue was simulated for both of lateral resolution enhancement and optical sectioning capacity in the same configuration. The results of onion cells and mouse liver tissue suggested that the proposed white-light structured illumination approach in FF-OCT demonstrates tomographic imaging for thick transparent samples with a higher lateral resolution and better contrast than standard FF-OCT. As a benefit of the fringe projection and low-coherence gate filtering, SI-FF-OCT also has optical sectioning capability in free of speckle-noise in sub-pixel accuracy way.