Fig. 1. Schematic of DHM with structured illumination.

Fig. 2. Resolution enhancement of DHM by the structured illumination. (a) Spectrum evolvement of the object wave during the imaging process. (b) Flowchart of the iteration process for resolution enhancement. The black dots denote high frequency components of the object; the red-dashed circles denote the NA of the optical system.

Fig. 3. Simulation results for resolution enhancement by structured illuminations. (a) Amplitude and (b) phase distributions of the simulated specimen. (c) Intensity distribution of the structured illumination along horizontal orientation. (d) and (e) Reconstructed amplitude images by using on-axis plane wave illumination and by structured illuminations with the proposed iterative method, respectively.

Fig. 4. Experimental results for resolution enhancement by structured illuminations. (a) Four phase gratings with different orientations loaded on SLM to generate structured illuminations. (b) Recorded hologram under one structured illumination. (c) and (d) The reconstructed phase images by using the on-axis plane wave illumination and by using the proposed iteration method, respectively.