“Single pulse coherence measurements in the water window at the free-electron laser FLASH” by Markus Osterhoff

Mai2013

• Single pulse coherence measurements in the water window at the free-electron laser FLASH
• D.D. Mai J. Hallmann T. Reusch M. Osterhoff S. Düsterer R. Treusch A. Singer M. Beckers T. Gorniak T. Senkbeil R. Dronyak J. Gulden O.M. Yefanov A. Al-Shemmary A. Rosenhahn A.P. Mancuso I.A. Vartanyants T. Salditt
• doi:10.1364/OE.21.013005
• Optics Express, 21, 13005–13017

• The spatial coherence of free-electron laser radiation in the water window spectral range was studied, using the third harmonic (λ₃=2.66 nm) of DESY's Free-electron LASer in Hamburg (FLASH). Coherent single pulse diffraction patterns of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilamellar lipid stacks have been recorded. The intensity histogram of the speckle pattern around the first lamellar Bragg peak, corresponding to the d=5 nm periodicity of the stack, reveals an average number of transverse modes of M̄=3.0 of the 3rd harmonic. Using the lipid stack as a “monochromator”, pulse-to-pulse fluctuations in the third harmonic λ₃ have been determined to be 0.033 nm.

• Free Electron Lasers, single pulses, coherence measurements, water window
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