학술논문
Bright Coherent Ultrahigh Harmonics in the keV X-Ray Regime from Mid-Infrared Femtosecond Lasers
Document Type
Working Paper
Author
Popmintchev, Tenio; Chen, Ming-Chang; Popmintchev, Dimitar; Arpin, Paul; Brown, Susannah; Ališauskas, Skirmantas; Andriukaitis, Giedrius; Balčiunas, Tadas; Mücke, Oliver; Pugzlys, Audrius; Baltuška, Andrius; Shim, Bonggu; Schrauth, Samuel E.; Gaeta, Alexander; Hernández-García, Carlos; Plaja, Luis; Becker, Andreas; Jaron-Becker, Agnieszka; Murnane, Margaret M.; Kapteyn, Henry C.
Source
Science 336(6086), 1287-1291 (2012)
Subject
Language
Abstract
High harmonic generation traditionally combines ~100 near-infrared laser photons, to generate bright, phase matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here we show that by guiding a mid-infrared femtosecond laser in a high pressure gas, ultrahigh harmonics can be generated up to orders > 5000, that emerge as a bright supercontinuum that spans the entire electromagnetic spectrum from the ultraviolet to > 1.6 keV, allowing in-principle the generation of pulses as short as 2.5 attoseconds. The multi-atmosphere gas pressures required for bright, phase matched emission also supports laser beam self-confinement, further enhancing the x-ray yield. Finally, the x-ray beam exhibits high spatial coherence, even though at high gas density, the recolliding electrons responsible for high harmonic generation encounter other atoms during the emission process.
Comment: 32 pages, 9 figures (4 in main text, 5 in supplemental materials)
Comment: 32 pages, 9 figures (4 in main text, 5 in supplemental materials)