Year: 2025
Type: article
Abstract: With the advancement of synchrotron and free-electron laser, X-ray quantum optics has emerged as a novel frontier for exploring light-matter interactions at high photon energies. A significant challenge in this field is achieving well-defined two-level systems through atomic inner-shell transitions, which are often hindered by broad natural linewidths and local electronic structure effects. This study aims to explore the potential of tungsten disilicide (WSi2) as a two-level system for X-ray quantum optics applications. Utilizing high-resolution resonant inelastic X-ray scattering (RIXS) near the W-L3 edge, in this work, the white line of bulk WSi2 is experimentally distinguished, overcoming the spectral broadening caused by short core-hole lifetime. The measurements are conducted by using a von Hamos spectrometer at the GALAXIES beamline of the SOLEIL synchrotron. The results reveal a single resonant emission feature with a fixed energy transfer, confirming the presence of a discrete 2p-5d transition characteristic of a two-level system. Additional high-resolution XAS spectra, obtained via high energy resolution fluorescence detection method and reconstructed from off-resonant emission (free from self-absorption effect for bulk WSi2 sample) method, further support the identification of a sharp white line. These findings demonstrate the feasibility of using WSi2 as a model system in X-ray cavity quantum optics and establish RIXS as a powerful technique to resolve fine inner-shell structures.
Source: Acta Physica Sinica
Authors: Zheqian ZHAO, Shuxing WANG, Xiyuan WANG, Yang SU, Ziru MA, Xinchao HUANG, Linfan ZHU, I. Physikalisches Institut, Justus-Liebig-Universität Gießen and Helmholtz Forschungsakademie Hessen für FAIR (HFHF), Campus Gießen, GSI Helmholtzzentrum für Schwerionenforschung, Gießen 35392, Germany, FXE instrument, European XFEL, Schenefeld 22869, Germany
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4412647383