Pumping a photoionization atomic inner-shell x-ray laser by x-ray free-electron laser radiation

Abstract

Focusing an x-ray free electron laser (XFEL) pulse into a gas target, a plasma of transiently core excited ions can be created within a few fs, building a pathway to an inner-shell keV x-ray laser. Varying the XFEL parameters, a wide variety of pulse structures can be created with comparable peak-intensities to XFELs: isolated pulses of subfs duration, trains of pulses with increased temporal coherence, and trains of fs pulses of different wavelengths. We present self-consistent gain and amplification calculations, tailored to predict first experiments on lasing in neon pumped by the Linac Coherent Light Source at Stanford.