Heidelberg 2015 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 46: Laser Applications: Laser Spectroscopy
Q 46.3: Vortrag
Mittwoch, 25. März 2015, 15:00–15:15, K/HS2
Near-edge x-ray absorption fine-structure at the carbon K-edge using a table-top coherent x-ray source — Seth L. Cousin1, Francisco Silva1, Stephan Teichmann1, Michael Hemmer1, •Bárbara Buades1, and Jens Biegert1,2 — 1ICFO - Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain — 2ICREA - Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
Attosecond soft-X-ray absorption spectroscopy elucidates dynamics in solids, 2D materials, magnetic structures or superconducting switches with unprecedented temporal resolution. We demonstrate the first high-flux table top attosecond source reaching the soft-X-ray water window, corresponding to wavelengths between 2.3 and 4.5 nm. The water window source, which contains the fundamental absorption edges of carbon, nitrogen and oxygen, now enables element-specific, high-resolution biological and molecular imaging, spectroscopy, materials science and observation of fundamental dynamics of matter at unprecedented timescales. We demonstrate our approach by retrieving the electronic structure of a solid state polyimide target with near-edge X-ray fine-structure absorption spectroscopy (NEXAFS) at the carbon K-edge (284 eV).
Our coherent soft x-ray source is based on high harmonic generation (HHG) with carrier to envelope-phase (CEP) stable sub-2-cycle laser pulses with a central wavelength at 1.85 µm. The generated broadband spectrum spans 200 eV to 530 eV thereby simultaneously covering the absorption edges of many relevant elements.