Diamond Zone Plates for XFELs

A growing number of experiments at X-ray free-electron lasers (XFELs) Need x-ray optical elements capable of collecting the largest possible fraction of the radiation and to focus into the smallest possible focus. Due to the high power levels of XFELs, radiation damage is a severe issue when using conventional diffractive optics. As a key step to avoid this problem, we develop diamond based Fresnel zone plates capable of withstanding the full beam of the world's most powerful x-ray laser. We measured a focal spot size down to 320 nm FWHM by the spectral band width of the source. A peak power density in the focal spot of 4x10¹⁷ W/cm² was obtained at 70 fs pulse length [1].

1. C. David, S. Gorelick, S. Rutishauser, J. Krzywinski, J. Vila-Comamala, V.A. Guzenko, O. Bunk, E. Färm, M. Ritala, M. Cammarata, D.M. Fritz, R. Barrett, L. Samoylova, J. Grünert and H. Sinn, Nanofocusing of hard X-ray free electron laser pulses using diamond based Fresnel zone plates,Scientific Reports 1 (2011) p. 57
2. P. Karvinen, C. Borca, M. Willimann, B. Meyer, M. Birri, D. Grolimund, J. Patommel, G. Wellenreuther, G. Falkenberg, M. Guizar-Sicairos, A. Menzel and C. David, Kinoform diffractive lenses for efficient nano-focusing of hard X-rays Optics Express 22 (2014) p. 16676