Fig. 1. Different wavefront slopes in each region focus at different positions.

Fig. 2. Geometry of beam propagation and wavefront retrieval scheme in terms of (a) a single beamlet and (b) the whole aperture.

Fig. 3. Simulation setup. (a) Simulation beamline. (b) Input intensity distribution. (c) Input wavefront distribution. (d) Output intensity distribution.

Fig. 4. Recovery process and results of simulation. (a) Sub-aperture division from Fig. 3(d). (b) Intensity distribution of one sub-aperture and (c) the corresponding Fourier distribution. (d) Recovered wavefront of the whole aperture. (e) Retrieval error compared with the original input wavefront. (f) Errors in the Zernike polynomial coefficients compared with the original phase.

Fig. 5. Experimental setup.

Fig. 6. Experimental results. (a) Phase distribution of CPP. (b) Recorded image with illustration of sub-aperture division and overlapping layout. (c) Fourier distribution of the chosen sub-aperture. (d) Recovered wavefront of the whole aperture. (e) Retrieval error compared with the phase distribution of the CPP. (f) Errors in Zernike polynomial coefficients compared with the original phase.

Table 1. Retrieval error for different sizes of sub-aperture and different overlaps.