Phase-matched extreme-ultraviolet frequency-comb generation

Abstract

Laser-driven high-order harmonic generation (HHG) provides tabletop sources of broadband extreme-ultraviolet (XUV) light with excellent spatial and temporal coherence. These sources are typically operated at low repetition rates, $f_{rep}\lesssim$100 kHz, where phase-matched frequency conversion into the XUV is readily achieved. However, there are many applications that demand the improved counting statistics or frequency-comb precision afforded by operation at high repetition rates, $f_{rep}$ > 10 MHz. Unfortunately, at such high $f_{rep}$, phase matching is prevented by the accumulated steady-state plasma in the generation volume, setting stringent limitations on the XUV average power. Here, we use gas mixtures at high temperatures as the generation medium to increase the translational velocity of the gas, thereby reducing the steady-state plasma in the laser focus. This allows phase-matched XUV emission inside a femtosecond enhancement cavity at a repetition rate of 77 MHz, enabling a record generated power of $\sim$2 mW in a single harmonic order. This power scaling opens up many demanding applications, including XUV frequency-comb spectroscopy of few-electron atoms and ions for precision tests of fundamental physical laws and constants.

9 pages, 4 figures

References in corpus (7)

• Generation of Spatially Coherent Light at Extreme Ultraviolet Wavelengths
• Extreme ultraviolet frequency comb metrology
• Efficient output coupling of intracavity high harmonic generation
• Ultrafast extreme ultraviolet photoemission without space charge
• Intervalley scattering in MoS${}_2$ imaged by two-photon photoemission with a high-harmonic probe
• Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy
• Nuclear effects in atomic transitions

Cited by in corpus (23)

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• Efficient nonlinear compression of a thin-disk oscillator to 8.5 fs at 55 W average power
• Concepts for direct frequency-comb spectroscopy of ${}^{229\text{m}}$Th and an internal-conversion-based solid-state nuclear clock
• The theory of direct laser excitation of nuclear transitions
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• Ultraviolet Dual Comb Spectroscopy: A Roadmap
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• Efficient Coherent XUV Generation and Manipulation in Microfluidic Glass Devices
• Resonant electronic-bridge excitation of the U-235 nuclear transition in ions with chaotic spectra
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• Extended model for optimizing high-order harmonic generation in absorbing gases
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• Phase cycling of extreme ultraviolet pulse sequences generated in rare gases
• High-brilliance ultra-narrow-band x-rays via electron radiation in colliding laser pulses
• Laser Driven Fluorescence Emission in a Nitrogen Gas Jet at 100 MHz Repetition Rate