LAUSR

Abstract We develop a method to retrieve small wave-front aberrations from a single far-field intensity. The solution specifies the even and odd parts of the unknown phase T in two separate equations. Both the odd part and the even part require only one focus intensity measurement with a given phase diversity produced by the deformable mirror or active surface system. We take the solution, the approximation of T, zero and random phase distributions as the initial guesses of GS (Gerchberg & Saxton) algorithm respectively, the final recovered TR is chosen from the one with the minimum amplitude Root Mean Squared Error (RMSE). Numerical simulation results show that the method works well when the root mean squared (RMS) of the phase error is less than 3.14 rad, and it is effective when the signal-to-noise ratio(SNR)>10. Phase ambiguity is solved by moving the deformable mirror twice according to the twin images TR and TR’ T R * , and the image with higher peak intensity is selected as the final estimation of T.