Bright Coherent Ultrahigh Harmonics in the keV X-ray Regime from Mid-Infrared Femtosecond Lasers
Open accessAbstract
From Long to Short: When you play a string instrument, you raise the frequency, or pitch, of the note by shortening the vibrating portion of the string: Drop the length in half, and you hear a harmonic at double the frequency. It is possible to do essentially the same thing with light waves by using selective excitation and relaxation processes of the electrons in crystals or high-pressure gases through which the beam of light is directed to produce light harmonics. Over the past decade, researchers have been optimizing the conversion of red light to the far edge of the ultraviolet, which corresponds to tens of harmonics. Popmintchev et al. (p. 1287 ) now show that mid-infrared light can undergo a process in high-pressure gas to generate ultrahigh harmonics up to orders greater than 5000 in the x-ray regime.
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In the 2010s, the ability to generate tunable mid-IR ultrashort pulses led to the realization that HHG scaling made it possible to phase-match the process into the soft x-ray region of the spectrum [129].
“In the 2010s, the ability to generate tunable mid-IR ultrashort pulses led to the further realization that HHG scaling made it possible to phase-match the process into the soft x-ray region of the spectrum (see figure 17) [129].”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
The use of OPAs has opened new research avenues in strong-field laser science and provided a unique tool to scale the HHG cut-off, generating ultrashort soft x-ray pulses up to the 1 keV range.
“The use of these OPAs has opened new research avenues in strong-field laser science, but has also provided a unique tool to scale the HHG cut-off, and thus to generate ultrashort soft x-ray pulses up to the 1 keV range of photon energies (see sections 5.1 and [129]).”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
Scaling the wavelength of the driver laser used in HHG has recently allowed increasing the high-energy cut-off of HHG spectra, and research groups are beginning to use broadband XUV continua extending into the water window.
“Scaling of, in particular, the wavelength of the driver laser used in the HHG process has recently allowed increasing the high-energy cut-off of HHG spectra [129], and these days an increasing number of research groups are beginning to use extremely broadband XUV continua that extend into the water window, i.e. the wavelength region where light elements like C, N and O have their K-edges”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
Using a MIR laser based on OPCPA (10 mJ, 80 fs, 3.9 μm, 20 Hz), phase-matched HHG up to 1.6 keV photon energy has been observed.
“Using a midinfrared (MIR) laser based on OPCPA (10mJ, 80 fs, 3.9 μm, 20 Hz), phase-matched HHG up to 1.6 keV of photon energy has been observed [129].”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
High-harmonic sources extended to soft x-ray domain are in principle capable of achieving attosecond durations and provide pulses perfectly synchronized with driving laser pulse.
“High-harmonic sources, which are being extended to the soft x-ray domain [129, 202, 203], are in principle clearly capable of achieving attosecond durations and provide pulses that are perfectly synchronized with the driving laser pulse.”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
Experiment confirms predictions that, using longer wavelength driving lasers, produces phase-matched emission to shorter wavelengths for fully phase-matched HHG in weakly ionized gasses.
“Experiment confirms predictions that, using longer wavelength driving lasers, produces phasematched emission to shorter wavelengths for fully phase-matched HHG in weakly ionized gasses[129].”
From Roadmap of ultrafast x-ray atomic and molecular physics (2018) · cites this paper as [129]
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Self-citation
- Authors
- Popmintchev, T., Chen, M.-C., Popmintchev, D., Arpin, P., Brown, S., Ališauskas, S., Andriukaitis, G., Balčiunas, T., Mücke, O. D., Pugzlys, A., Baltuška, A., Shim, B., Schrauth, S. E., Gaeta, A., Hernández-García, C., Plaja, L., Becker, A., Jaron-Becker, A., Murnane, M. M., & Kapteyn, H. C.
- Affiliations
- Joint Institute for Laboratory Astrophysics (US)
- TU Wien (AT)
- Photonics Institute, Vienna University of Technology, Vienna A-1040, Austria.
- Cornell University (US)
- Universidad de Salamanca (ES)
- JILA, University of Colorado at Boulder, Boulder, CO 80309, USA.
- Corresponding author
- Popmintchev, Tenio
- ORCID
- Venue
- Science
- Published
- 2012-06-08
- Volume
- 336
- Issue
- 6086
- Pages
- 1287-1291
- ISSN
- 0036-8075 (ISSN-L)
- 1095-9203
- OpenAlex
- W2093889451
- Cited by
- 1,830
- References
- 46
- Citations by year
- 2026: 85 · 2025: 93 · 2024: 100 · 2023: 107 · 2022: 132 · 2021: 111 · 2020: 143 · 2019: 154 · 2018: 125 · 2017: 140 · 2016: 184 · 2015: 176 · 2014: 155 · 2013: 98 · 2012: 27
- FWCI
- 75.36
- Type
- journal article
- Language
- en
- Open access
- green
- doi.org
- Licence
- other-oa
- Locations
- Science (publishedVersion)
- PubMed (publishedVersion)
- Hispana (publishedVersion, other-oa)
- arXiv (Cornell University) (submittedVersion, cc-by-nc-nd)
- Gredos (University of Salamanca) (submittedVersion, other-oa)
- arXiv (Cornell University)
- Funders
- National Science Foundation
- Austrian Science Fund
- Österreichische Forschungsförderungsgesellschaft
- Junta de Castilla y León (FIS2009-09522)
- U.S. Air Force (FA9550)
- Topics
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Laser-Matter Interactions and Applications
- Physical Sciences › Physics and Astronomy › Radiation › Advanced X-ray Imaging Techniques
- Physical Sciences › Engineering › Electrical and Electronic Engineering › Photonic Crystal and Fiber Optics
- Keywords
- high harmonic generation, keV X-rays, supercontinuum, phase matching, high-pressure gas, spatial coherence, attosecond pulses, electron recollision
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