Holographic tomography with object rotation and two-directional off-axis illumination.

A hybrid system of holographic tomography, which utilizes rotation of a sample and two-directional, off-axis illumination is proposed. The applied type of illumination brings two major benefits. First, it offers theoretical potential for the resolution improvement with respect to conventional tomography. Second, it enables effective, numerical compensation of the defocus error, which is achieved with an accurate, noise-immune autofocusing. Hence, the main practical obstacle of hybrid tomography is removed and its high-resolution potential is put into practice. The utility of the proposed concept is experimentally demonstrated with the tomographic measurement of a photonic crystal fiber.