Extreme Ultraviolet Radiation With Coherence Time Greater Than 1 s

Abstract

Many atomic and molecular systems of fundamental interest possess resonance frequencies in the extreme ultraviolet (XUV) where laser technology is limited and radiation sources have traditionally lacked long-term phase coherence. Recent breakthroughs in XUV frequency comb technology have demonstrated spectroscopy with unprecedented resolution at the megahertz level, but even higher resolutions are desired for future applications in precision measurement. By characterizing heterodyne beats between two XUV comb sources, we demonstrate the capability for sub-hertz spectral resolution. This corresponds to coherence times >1 s at photon energies up to 20 eV, more than six orders of magnitude longer than previously reported. This work establishes the ability of creating highly phase-stable radiation in the XUV with performance rivaling that of visible light. Furthermore, by direct sampling of the phase of the XUV light originating from high-harmonic generation, we demonstrate precise measurements of attosecond strong-field physics.

References in corpus (5)

• Extreme ultraviolet frequency comb metrology
• Hole transitions in multiply-charged ions for precision laser spectroscopy and searching for alpha-variation
• Efficient output coupling of intracavity high harmonic generation
• Ramsey-comb spectroscopy with intense ultrashort laser pulses
• Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

Cited by in corpus (19)

• High-harmonic generation in amorphous solids
• Frequency ratio of the ${}^{229\mathrm{m}}$Th nuclear isomeric transition and the ${}^{87}$Sr atomic clock
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• The ${}^{229}$Th isomer: prospects for a nuclear optical clock
• Noncollinear enhancement cavity for record-high out-coupling efficiency of an extreme-UV frequency comb
• Concepts for direct frequency-comb spectroscopy of ${}^{229\text{m}}$Th and an internal-conversion-based solid-state nuclear clock
• XUV frequency comb operation in an astigmatism-compensated enhancement cavity
• Tunable VUV Frequency Comb for ${}^{229m}$Th Nuclear Spectroscopy
• High-Precision Ramsey-Comb Spectroscopy Based on High-Harmonic Generation
• Simple phase noise measurement scheme for cavity-stabilized laser systems
• Ultraviolet Dual Comb Spectroscopy: A Roadmap
• Cavity-enhanced field-free molecular alignment at a high repetition rate
• Cavity-enhanced ultrafast two-dimensional spectroscopy using higher-order modes
• Interrogating the temporal coherence of EUV frequency combs with highly charged ions
• Ultrastable optical, XUV and soft-x-ray clock transitions in open-shell highly charged ions
• Demonstration of Ramsey-Comb Precision Spectroscopy in Xenon at Vacuum Ultraviolet Wavelengths Produced with High-Harmonic Generation
• A continuous-wave vacuum ultraviolet laser for the nuclear clock
• Backaction-free measurement of quantum correlations via quantum time-domain interferometry