2D-RIXS: resonant inelastic X-ray scattering microscopy with high energy and spatial resolutions.

A two-dimensional resonant inelastic X-ray scattering (2D-RIXS) microscopy system has been developed at beamline BL02U of NanoTerasu. The instrument combines a Wolter type-I mirror for spatial imaging with a varied-line-spacing grating spectrometer, simultaneously achieving micrometre-scale spatial resolution and ultrahigh energy resolution in the soft X-ray regime. Test chart measurements confirm a vertical spatial resolution of 1.0 µm near the field-of-view center, and the horizontal resolution determined by the incident beam footprint is 0.8 µm. RIXS imaging capabilities have been demonstrated by the measurements of a patterned NanoTerasu logo and exfoliated NiPS3 nanoflakes, highlighting its efficiency in locating specific microscale regions within inhomogeneous samples. These results establish 2D-RIXS microscopy as a position-sensitive probe of elementary excitations in quantum materials and functional devices.