Computed tomography of cylindrically symmetric object by use of digital holography

Digital holographic tomography, a computed tomography by use of digital holography, has a huge potential for three-dimensional imaging of weakly-diffracting phase objects. But the need of multiple angles of illumination weakened imaging capability of dynamic objects. For cylindrically symmetric object, we can use complex amplitude data of single hologram under zero incidence angles to replace the other complex amplitude data under different incidence angles. Therefore, it is possible to achieve the dynamic imaging of cylindrically symmetric objects. The digital holographic tomography can provide a way for the dynamic imaging of phase-type objects having a cylindrically symmetric structure. We report an experimental example of the capillary tube having a cylindrically symmetric structure. Tomography of the capillary tube is performed by filtered back-projection algorithm and Fourier diffraction algorithm respectively to reconstruct the 3-D map of refractive index. Experimental results show that, comparing with the filtered back-projection reconstruction, diffraction tomography based on the Rytov approximation better respects the dimensions of the capillary tube.