Synthetic Fourier Domain Optical Coherence Tomography

A novel approach for image formation in optical coherence tomography (OCT) and microscopy is presented. The depth resolution of OCT, including recently developed nanosensitive OCT (nsOCT), is limited by the spectral bandwidth of the light source used for illumination. The proposed approach, synthetic OCT (synOCT), permits label-free, depth-resolved quantitative visualization of the subwavelength-sized structures with nanosensitivity. Using synOCT it is possible to estimate the contribution of axial Fourier components of an object's structure in image formation at each small volume within the image. The size of such areas can be smaller than the resolution limit of the imaging system that provides potential for super-resolution imaging. Visualization of the subwavelength periodic structures and quantitative visualization of the subwavelength internal structures of highly scattering biological samples, within voxels smaller than resolution limit of the imaging system, are demonstrated. In contrast to nsOCT, the trade-off between spectral and spatial resolution is removed which results in dramatic improvement of both spectral and spatial resolution in synOCT relative to nsOCT. A novel approach to image formation in optical coherence tomography (OCT), synthetic OCT (synOCT), is reported. The approach is based on reconstruction of the axial spatial harmonics of the object's structure within detected bandwidth. The synOCT permits to access the subwavelength structure at areas smaller than resolution limit of the imaging system, with nanosensitivity to structural changes, and opens new possibility for super-resolution imaging.image (c) 2024 WILEY-VCH GmbH