Fig. 1. Block diagram of the iterative phase retrieval algorithm

Fig. 2. Schematic diagram of the optical structure

Fig. 3. Relationship between the correlation coefficient of PSF at different wavelengths and Δλ

Fig. 4. Simulation results. (a) Speckle pattern at wavelength of 450 nm; (b) autocorrelation of Fig.(a); (c) reconstruction result of Fig.(b); (d) autocorrelation of O_M; (e) superposition of autocorrelations of speckle patterns generated by multi-wavelength; (f) reconstruction result of Fig.(e)

Fig. 5. Experimental results. (a) Speckle pattern at wavelength of 450 nm; (b) amplitude spectrum of Fig.(a); (c) reconstruction result of Fig.(b); (d) amplitude spectrum of the target; (e) averaged amplitude spectrum of speckle patterns generated by multi-wavelength; (f) reconstruction result of Fig.(e)