Fig. 1. The determination ofinitial phase

Fig. 2. The influence of parameter a and b on the output beam

Fig. 3. The flowchart of the algorithm

Fig. 4. Diffraction efficiency and uniformity error

Fig. 5. The simulation results of the annular flat-top beam

Fig. 6. Experimental setup and the intensity distribution of Gaussian beam

Fig. 7. The experimental results of proposed method

Fig. 8. The experimental results of traditional GS algorithm

Fig. 9. Effect of Gaussian spot with different waist radius on output beam