X-ray Optics for XFELs

Current Research Topics

• Diamond Fresnel Zone Plates 
• Beam Splitter Gratings for Spectral Monitoring
• A Delay Line for Ultrafast Pump-Probe Experiments
• X-ray Streaking using off-axis Fresnel Zone Plates

The advent of X-ray free electron lasers (XFELs) providing extremely intense X-ray pulses has opened possibilities for novel experiments in condensed matter physics and structural biology. At the same time, it poses new challenges to the instrumentation used at these facilities. We are collaborating with scientist at many XFELS, including LCLS, SACLA, FLASH, FERMI, and SwissFEL to develop innovative solutions based on diffractive optics:

• The high radiation heat loads can quickly damage conventional optics such as Fresnel zone plates or diffraction gratings. To overcome this limitation, the X-ray Optics and Applications group has pioneered the fabrication of diffractive X-ray optics made of diamond that can sustain the full XFEL beams.
   
• The strong spectral and intensity fluctuation inherent to the self-amplified spontaneous emission of XFELs frequently cause severe problems during data analysis. We work on providing solutions for monitoring of beam parameters and for normaliziation on a shot-to-shot basis.
   
• By exploiting the time-dispersive properties of diffractive x-ray optics, we have implemented several novel approaches based on diffractive X-ray elements to enable experimental schemes at XFELs for ultra-fast time-resolved measurements.