Micro- and Nanofocus Characterization by Ablative Imprints at SQS and HED Instruments

Abstract

Accurate characterization of the fluence distribution [J/cm2] in the focus of ultra-high intensity laser beams is of great importance in experiments investigating laser-matter interactions. We studied the fluence distribution in the laser beam focus utilizing the well-established direct method of ablative imprints. The method is based on creating cross-sections of the fluence profile at varied fluence levels by imprinting the beam into a thin layer of PbI2 deposited on a CVD diamond. We present our characterization of a (not optimally) focused beam tuned by KB adaptive mirrors at the Small Quantum

Systems instrument of the EuXFEL and a nanofocus created by a compound refractive lens at the High Energy Density instrument of the EuXFEL.