Demonstration of High-Brightness and High-Resolution Coded-Source Radiography Driven by Picosecond Lasers

Picosecond petawatt laser-driven X-rays provide a powerful diagnostic tool for high-energy-density physics with high spatial resolution. In such experiments, point-projection backlighting is employed, where a quasi-point X-ray source is routinely generated by laser irradiating a wire target. The imaging spatial resolution is inherently related to the source size. This leads to a trade-off between spatial resolution and laser-to-target interception, and thus inhibits the improvement of source brightness. Coded-source radiography provides an alternative approach, which uses structured source target with high interception to form coded images, and reconstructs the high-resolution images based on source position function. Here, we demonstrate the generation of an annular X-ray source driven by a picosecond laser. By using a large-diameter target to fully intercept the laser, we achieved an annular X-ray source with the brightness several-fold higher than that of the conventional quasi-point source produced by a wire target. Coded-source radiography with this annular source maintained a high spatial resolution, and yielded a significantly higher signal-to-noise ratio (SNR) than the conventional point-projection imaging. Our findings highlight that this technique can provide clearer and more detailed radiography for high-energy-density physics experiments conducted in challenging environments.