AP-Seminar: Stimulated X-Ray Raman Scattering in Atomic and Molecular Gases

X-ray free-electron lasers (XFELs) provide ultra-short x-ray pulses of unprecedented peak brightness, opening a pathway to transfer quantum electronics and quantum optical processes to the x-ray domain. We present results of the first experimental demonstration of an x-ray laser based on amplification of x-ray radiation on an atomic inner-shell transition in neon. The population inversion is achieved by rapid K-shell photo-ionization or resonant excitation with an XFEL pulse. Gain saturation of the K-α transition in neon could be demonstrated in a recent experiment at the Linac Coherent Light Source. In addition to experimental results, we present numerical solutions of the generalized Maxwell-Bloch equations. The emitted x-ray pulses have ultra-short time durations, ranging from sub femtoseconds to a few femtoseconds and are nearly transform limited, despite pumping with a stochastic XFEL source of only limited temporal coherence. We will discuss the extension of the x-ray lasing scheme to amplified spontaneous emission and self-stimulated x-ray Raman scattering in diatomic molecules, thereby creating a tunable x-ray laser based on inner-shell transitions in molecules.