Single-frame far-field diffractive imaging with randomized illumination

TL;DR

The paper presents randomized probe imaging (RPI), a single-frame diffractive imaging technique using structured speckle illumination for robust, quantitative phase imaging with simple setup, demonstrated with visible light and soft X-ray experiments.

Contribution

Introduction of RPI, a novel single-frame imaging method that simplifies setup and enhances robustness for quantitative phase imaging.

Findings

Reliable reconstructions achieved with RPI

Applicable to extended samples without near-field optics

Demonstrated with visible light and soft X-ray experiments

Abstract

We introduce a single-frame diffractive imaging method called randomized probe imaging (RPI). In RPI, a sample is illuminated by a structured probe field containing speckles smaller than the sample's typical feature size. Quantitative amplitude and phase images are then reconstructed from the resulting far-field diffraction pattern. The experimental geometry of RPI is straightforward to implement, requires no near-field optics, and is applicable to extended samples. When the resulting data are analyzed with a complimentary algorithm, reliable reconstructions which are robust to missing data are achieved. To realize these benefits, a resolution limit associated with the numerical aperture of the probe-forming optics is imposed. RPI therefore offers an attractive modality for quantitative X-ray phase imaging when temporal resolution and reliability are critical but spatial resolution in the tens of nanometers is sufficient. We discuss the method, introduce a reconstruction algorithm, and present two proof-of-concept experiments: one using visible light, and one using soft X-rays.