Figure 5. Reconstruction of sub-pixel patterns with phase.

The sparsity algorithm was extended to recover both the amplitude and the phase of object patterns. (A) Objects with a uniform, nominal phase values (0.1, 0.3 and 0.5) were tested. From simulated holograms, the sparsity algorithm recovered the phase information. The relative error decreased, as the phase contrast between the object and the background increased. (B) A non-symmetric pattern with sub-pixel features and varying phases was tested. The smallest feature size was 1.1 μm. The algorithm not only achieved sub-pixel resolution, but also restored accurate amplitude and phase values. Holograms were simulated for a 2.2-μm pixel imager.