X-Ray Talbot Interferometry for High Energy Density Science

X-ray imaging is a well-established diagnostic in high energy density physics and is widely used to probe matter under extreme conditions. Conventional X-ray radiography, however, is intrinsically limited to measuring the absorption of penetrating X-rays. In many laser-driven experiments, especially those involving low-Z materials, absorption contrast can be weak. Talbot interferometry extends conventional X-ray imaging by employing a grating interferometer to additionally measure the X-ray's phase signal. This phase information provides complementary sensitivity to gradients in electron density, improving the diagnostic capabilities for low-absorbing materials. Although Talbot interferometry is well established at synchrotron and laboratory X-ray sources, its application to laser-driven experiments presents significant challenges due to single-shot operation, high demands on spatial resolution and intense self emission from the observed object.

In this talk, I present a Talbot interferometer with a laser-produced X-ray backlighter source, implemented at two different high-power laser facilities. With this setup, we successfully demonstrate grating-based X-ray phase-contrast imaging of shock-wave propagation in solid plastic and low-density plastic foam targets, showing its applicability to equation-of-state measurements and laboratory astrophysics. Furthermore, we use grating-based X-ray dark-field imaging, another imaging modality of Talbot interferometry, to probe the homogenization of inertial confinement fusion (ICF) relevant foam targets, i.e. the transition of a microstructured foam into a homogeneous plasma.