Publications associated with Intense X-ray-Matter Interactions

Achieving microfocus of the 13.5-NM flash beam for exploring matter under extreme conditions

FEL 2009 - 31st International Free Electron Laser Conference (2009) 784-788

AJ Nelson, RW Lee, S Toleikis, S Bajt, RR Fäustlin, H Chapman, J Krzywinski, J Chalupsky, L Juha, V Hajkova, B Nagler, SM Vinko, T Whitcher, JS Wark, T Dzelzainis, D Riley, K Saksl, AR Khorsand, R Sobierajski, M Jurek, J Andreasson, N Timneanu, J Hadju, M Fajardo, T Tschentscher

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: δ=13.5 nm, pulse length 15 fs, pulse energy 10-40 μJ, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) - PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of ≤1 μm producing intensities greater than 1016 W cm-2. Observations were correlated with simulations of best focus to provide further relevant information. This focused XUV laser beam now allows us to begin exploring matter under extreme conditions.

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