Optimized phase retrieval method based on multi-focus property of zone plate

Abstract

As a computational imaging method, phase retrieval has wide applications in image reconstruction, wavefront detection, image encryption, etc. It is an image-based wavefront sensing technique and compared with some other traditional measurement methods such as interferometry, phase retrieval has the advantages of easy operation, high accuracy and strong adaptability to the environment. Conventional phase retrieval algorithms, such as the Gerchberg–Saxton (GS) algorithm, retrieve wavefront by iterative calculation. But limited by finite information of the captured diffractive light filed, the calculation process is easy to fall into local minimum value and stagnation occurs in practical, making it unable to converge to the right wavefront. In this paper, in order to improve this phenomenon, a phase retrieval method combined with the zone plate is proposed in this paper. In this method, zone plates are added into the traditional iterative phase retrieval algorithm to modulate the incident wavefront and combined with the multi-focus property, it can collect more effective information about the wavefront in a single optical intensity distribution image and realize a better wavefront reconstruction result. Simulation results indicate that by taking zone plates into calculation, more effective reconstruction results can be acquired. On the one hand, the recovery residual is smaller compared with conventional lens. On the other, although all of these methods reach to a stagnation, zone-plate-based methods are more efficient to get a better result.