High-speed single-shot multiplane phase retrieval using quadratic distorted gratings for coherent diffraction imaging

Abstract

Multi-plane coherent diffraction imaging reconstructs complex light fields from multiple axial diffraction intensities. However, the time overhead caused by multiple recordings limits the observation of fast dynamic processes, and the offset error during motion affects the reconstruction performance. We introduce a novel phase-retrieval method capable of capturing diffraction patterns from multiple planes in a single exposure, avoiding mechanical motion inherent in traditional methods. This method exploits the unique feature of quadratic distorted gratings, which have different focal lengths at different diffraction orders, thereby enabling the transportation of light fields from multiple planes to distinct regions within the detection plane and achieving spatial multiplexing. To recover the amplitude and phase maps from the segmented sub-intensity sequences within the detection plane, we employed an efficient algorithm known as single-beam multiple-intensity reconstruction with dual mean. The feasibility of the proposed method was validated through reconstruction experiments involving resolution targets and phase plates. Furthermore, given that the modulator used is a self-supporting pure amplitude element, this method is highly suitable for phase imaging with high spatiotemporal resolution in extreme ultraviolet, X-rays, and other short-wavelength segments.