A method is proposed to compute and synthesize a nano-optical element to produce a new visual effect: 3D image formed in the vicinity of zero diffraction order. The main idea of the new method is to set large viewing zone with the center at zero order (not as narrow band at +1st order like in traditional Benton’s rainbow 3D holograms). A synthesis technology is developed incorporating computation of the phase function of the entire optical element, and the formation its microrelief using e-beam lithography with an accuracy of 10 nm in terms of microrelief depth. The resulting 3D image can be observed well when illuminated by white light, and an observer sees the 3D image with full parallax, both when the optical element is tilted and even when it is rotated through 360 degrees. In addition, unlike rainbow holograms, the color of the formed 3D image does not depend on the viewing angle – in other words, the formed 3D image behaves like a real 3D object. The method also allows fragments of diffraction gratings to be embedded into the nano-optical element to form an additional 2D image visible at an acute angle.
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