Phase retrieval based on transport of intensity equation with two-wavelength illuminations

The transport of intensity equation (TIE) has established the relationship between the phase of an optical field and the variation of its intensity along the direction of propagation. In this paper, a new method based on TIE used for two-wavelength phase retrieval has been proposed. The TIE is solved by employing the regularized Fourier-transform-based-approach under two separate wavelengths, gaining two phases. Combined with the synthetic wavelength, the method consists of the combination and generation of the two phases which are applied to calculate the synthetic phase for reconstructing the best phase result. Numerical experiments are presented to demonstrate the wider application and accuracy of our proposed method.