Proceedings PaperOptical array imaging system using digital phase conjugation: proposal of an optimum data selecting method
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An optical array imaging method using digital phase conjugation has previously been proposed for diffraction-limited imaging ofobjects with no effects ofmisalignments ofarray elements. After collecting a set ofarray data this method iteratively receives the reflected wave from the object and retransmits its phase-conjugated wave until convergence is reached which are carried out all on a computer using the data. When the object has for example two points with similar maximum reflectivities however the method sometimes gives rise to doubled images. In this article the array data is selectively used in the iterative process to avoid such doubled images. Some numerical examples are presented. PRINCIPLE A schematic of optical array imaging system is shown in Fig. 1 where the object is illuminated from one of the array elements and the reflected light is received by the whole elements. The light is then interfered with a reference light to detect the complex-amplitude of the optical field. This is repeated for the illumination from each array element and a set of array data are obtained s(f JJh(f Object Array m n l . . N (1) F ig. 1 Schematic ofoptical array imaging where h(f x) is the wave propagation function o(x) is system using digital phase conjugation the coefficient of reflectivity ofthe object and effects of misalignments are included in h(f x) . The subsequent processing is carried out all on a computer.