The phase-diversity wavefront sensor is a popular means for conducting quantitative wavefront measurements and image restoration from several desired intensity measurements. It has wide applications ranging from adaptive optics in telescopes to optical detection in high-power laser systems. In contrast to traditional phase diversity, we propose a modified version of single-shot quasi-phase-diversity wavefront sensing using a multifocal Fibonacci zone-plate module. The Fibonacci zone plate, designed to generate a specific separation distance between the in-focus and defocused diffraction planes, enables recording multiplanar diffraction patterns at a given position under a single exposure. Thus, this modified wavefront sensing can improve recovery accuracy and realize real-time measurements via a single exposure. In our experiment, a test object fabricated on a chrome plate was measured to verify the validity of the proposed single-shot quasi-phase-diversity wavefront sensing. With the advantages of simple real-time operation and improved measurement accuracy, this technique can be applied to various detection and imaging processes, such as wavefront measurements and image restoration.

Coherent diffractive imaging (CDI) is an imaging technique that directly recovers the amplitude and phase information of the test object from the recorded diffraction patterns with an iterative algorithm. Different from the traditional CDI, here an image-plane CDI is proposed based on the variable-ratio lateral-shearing interferometry. Variable-ratio operation can realize three optical functions, the first is the array imaging, the second is the image relay, and the third is variable-ratio shear. In experiment, a frame of 2×2 array diffraction patterns is recorded in one single exposure. Then, each sub-diffraction pattern is extracted through the image features and is sequentially used to recover the test object by phase retrieval. The experimental results of phase-only and amplitude-only object verify the effectiveness and robustness of our proposed method. This method not only circumvents the calibration problem of gratings but also strengthens the convergence conditions required for phase retrieval, which has broad applications in fields such as optical imaging and wavefront sensing.