Spot size characterization of focused non-Gaussian X-ray laser beams

• Published in: Optics express Vol. 18; no. 26; pp. 27836 - 27845
• Main Authors: Chalupský, J, Krzywinski, J, Juha, L, Hájková, V, Cihelka, J, Burian, T, Vysín, L, Gaudin, J, Gleeson, A, Jurek, M, Khorsand, A R, Klinger, D, Wabnitz, H, Sobierajski, R, Störmer, M, Tiedtke, K, Toleikis, S
• Format: Journal Article
• Language: English
• Published: United States 20-12-2010
• Subjects: Computer Simulation; Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Lasers; Light; Models, Statistical; Normal Distribution; Scattering, Radiation; X-Rays
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.18.027836

We present a new technique for the characterization of non-Gaussian laser beams which cannot be described by an analytical formula. As a generalization of the beam spot area we apply and refine the definition of so called effective area (A(eff)) [1] in order to avoid using the full-width at half maximum (FWHM) parameter which is inappropriate for non-Gaussian beams. Furthermore, we demonstrate a practical utilization of our technique for a femtosecond soft X-ray free-electron laser. The ablative imprints in poly(methyl methacrylate) - PMMA and amorphous carbon (a-C) are used to characterize the spatial beam profile and to determine the effective area. Two procedures of the effective area determination are presented in this work. An F-scan method, newly developed in this paper, appears to be a good candidate for the spatial beam diagnostics applicable to lasers of various kinds.