Generation of bright isolated attosecond soft X-ray pulses driven by multicycle midinfrared lasers

Journal Article · Wed May 21 00:00:00 EDT 2014 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.1407421111· OSTI ID:1686112

Chen, Ming -Chang ^[1]; Mancuso, Christopher ^[2]; Hernandez-Garcia, Carlos ^[3]; Dollar, Franklin ^[2]; Galloway, Ben ^[2]; Popmintchev, Dimitar ^[2]; Huang, Pei -Chi ^[4]; Walker, Barry ^[5]; Plaja, Luis ^[6]; Jaro -Becker, Agnieszka A. ^[2]; Becker, Andreas ^[2]; Kapteyn, Henry C. ^[2]; Popmintchev, Tenio ^[2]; Murnane, Margaret M. ^[2]

---

1. Univ. of Colorado, Boulder, CO (United States); National Tsing Hua Univ., Hsinchu (Taiwan); JILA/University of Colorado Boulder
2. Univ. of Colorado, Boulder, CO (United States)
3. Univ. of Colorado, Boulder, CO (United States); Univ. de Salamanca (Spain)
4. National Tsing Hua Univ., Hsinchu (Taiwan)
5. Univ. of Delaware, Newark, DE (United States)
6. Univ. de Salamanca (Spain)

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, to date the shortest subfemtosecond (attosecond, 10-18 s) pulses have been produced only in the extreme UV region of the spectrum below 100 eV, which limits the range of materials and molecular systems that can be explored. Here we experimentally demonstrate a remarkable convergence of physics: when midinfrared lasers are used to drive high harmonic generation, the conditions for optimal bright, soft X-ray generation naturally coincide with the generation of isolated attosecond pulses. The temporal window over which phase matching occurs shrinks rapidly with increasing driving laser wavelength, to the extent that bright isolated attosecond pulses are the norm for 2-μm driving lasers. Harnessing this realization, we experimentally demonstrate the generation of isolated soft X-ray attosecond pulses at photon energies up to 180 eV for the first time, to our knowledge, with a transform limit of 35 attoseconds (as), and a predicted linear chirp of 300 as. Most surprisingly, advanced theory shows that in contrast with as pulse generation in the extreme UV, long duration, 10-cycle, driving laser pulses are required to generate isolated soft X-ray bursts efficiently, to mitigate group velocity walk-off between the laser and the X-ray fields that otherwise limit the conversion efficiency. Furthermore, our work demonstrates a clear and straightforward approach for robustly generating bright isolated attosecond pulses of electromagnetic radiation throughout the soft X-ray region of the spectrum.

• Research Organization: Univ. of Colorado, Boulder, CO (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
• Grant/Contract Number: FG02-99ER14982
• OSTI ID: 1686112
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 23 Vol. 111; ISSN 0027-8424
• Publisher: National Academy of Sciences
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
Ultrafast
coherent
nonlinear optics