1. Bright Coherent Ultrahigh Harmonics in the keV X-Ray Regime from Mid-Infrared Femtosecond Lasers
- Author
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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., and Kapteyn, Henry C.
- Subjects
Physics - Optics ,Physics - Atomic Physics ,Quantum Physics - 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)
- Published
- 2024
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