Micro-Focusing of Broadband High-Order Harmonic Radiation by a Double Toroidal Mirror

• Published in: Applied sciences 2017-11, Vol.7 (11), p.1159
• Main Authors: Coudert-Alteirac, Hélène, Dacasa, Hugo, Campi, Filippo, Kueny, Emma, Farkas, Balázs, Brunner, Fabian, Maclot, Sylvain, Manschwetus, Bastian, Wikmark, Hampus, Lahl, Jan, Rading, Linnea, Peschel, Jasper, Major, Balázs, Varjú, Katalin, Dovillaire, Guillaume, Zeitoun, Philippe, Johnsson, Per, L’Huillier, Anne, Rudawski, Piotr
• Format: Article
• Language: English
• Subjects: Aluminum; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Attosecond pulses; Back propagation; Bandwidths; Broadband; Experiments; Extreme ultraviolet; Fysik; Gases; Harmonic radiation; High-order harmonic generation; Lasers; Measurement techniques; Microfocusing; Natural Sciences; Naturvetenskap; Optics; Optimization; Physical Sciences; Radiation; Sensors; Ultrafast nonlinear optics; Ultraviolet radiation; Wave propagation; Wavefront sensing; XUV focusing
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app7111159

We present an optical system based on two toroidal mirrors in a Wolter configuration to focus broadband extreme ultraviolet (XUV) radiation. Optimization of the focusing optics alignment is carried out with the aid of an XUV wavefront sensor. Back-propagation of the optimized wavefront to the focus yields a focal spot of 3.6 × 4.0 µm2 full width at half maximum, which is consistent with ray-tracing simulations that predict a minimum size of 3.0 × 3.2 µm2. This work is important for optimizing the intensity of focused high-order harmonics in order to reach the nonlinear interaction regime.