The physics and chemistry of liquid solutions play a central role in science, and our understanding of life on Earth. Unfortunately, key tools for interrogating aqueous systems, such as infrared and soft X-ray spectroscopy, cannot readily be applied because of strong absorption in water. Here we use gas-dynamic forces to generate free-flowing, sub-micron, liquid sheets which are two orders of magnitude thinner than anything previously reported. Optical, infrared, and X-ray spectroscopies are used to characterize the sheets, which are found to be tunable in thickness from over 1 μm down to less than 20 nm, which corresponds to fewer than 100 water molecules thick. At this thickness, aqueous sheets can readily transmit photons across the spectrum, leading to potentially transformative applications in infrared, X-ray, electron spectroscopies and beyond. The ultrathin sheets are stable for days in vacuum, and we demonstrate their use at free-electron laser and synchrotron light sources.

Advanced Light Source Lawrence Berkeley National Laboratory Berkeley CA 94720 USA

Department of Electrical and Computer Engineering University of Alberta Edmonton AB T6G 1H9 Canada

Deutsches Elektronen Synchrotron DESY Notkestraße 85 Hamburg D 22607 Germany

ELI Beamlines Institute of Physics of the Czech Academy of Sciences Na Slovance 2 Prague 18221 Czech Republic

European 10 Ray Free Electron Laser Facility GmbH Schenefeld 22869 Germany

SLAC National Accelerator Laboratory Menlo Park CA 94720 USA

Thayer School of Engineering Dartmouth College 14 Engineering Dr Hanover NH 03755 USA

Nat Commun. 2018 Jul 17;9(1):2860. doi: 10.1038/s41467-018-05365-4. PubMed

Nat Commun. 2019 Apr 3;10(1):1615. doi: 10.1038/s41467-019-09457-7. PubMed

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