Phase space optics allows the four-dimensional simultaneous visualization of both space and spatial frequency optical information. The Wigner distribution function (WDF) is a common characterization of the phase space. Compared with the two-dimensional complex amplitude coherent optical field, the WDF can characterize optical field with arbitrary coherent states due to its higher dimensions. It is especially advantageous for the representation of partially coherent optical fields. The WDF is real and may have negative values, which are the result of phase-space interference. In this paper, an improved phase-space retrieval method is demonstrated. First, capture three-dimensional intensity focal stack. Then, phase space tomography (PST) combined with a non-linear iterative projection algorithm is conducted to reconstruct the whole WDF. We further analyzed the effect of the microscopy imaging system, i.e., the illumination aperture and the aperture of objective lens effect.
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