Stimulated resonant inelastic X-ray scattering in a solid

When materials are exposed to X-ray pulses with sufficiently high intensity, various nonlinear effects can occur. The most fundamental one consists of stimulated electronic decays after resonant absorption of X-rays. Such stimulated decays enhance the number of emitted photons and the emission direction is confined to that of the stimulating incident photons which clone themselves in the process. Here we report the observation of stimulated resonant elastic (REXS) and inelastic (RIXS) X-ray scattering near the cobalt L-3 edge in solid Co/ Pd multilayer samples. We observe an enhancement of order 10(6) of the stimulated over the conventional spontaneous RIXS signal into the small acceptance angle of the RIXS spectrometer. We also find that in solids both stimulated REXS and RIXS spectra contain contributions from inelastic electron scattering processes, even for ultrashort 5 fs pulses. Our results reveal the potential and caveats of the development of stimulated RIXS in condensed matter.

Automated summary

When materials are exposed to X-ray pulses with high intensity, various nonlinear effects, including stimulated electronic decays, can occur. In this study, we observed stimulated resonant elastic (REXS) and inelastic (RIXS) X-ray scattering near the cobalt L-3 edge in solid Co/Pd multilayer samples. Our findings show that the stimulated REXS and RIXS spectra in solids contain contributions from inelastic electron scattering processes, even with ultrashort 5 fs pulses. These results demonstrate the potential and considerations for the development of stimulated RIXS in condensed matter.