| 1. |
- De Angelis, D., et al.
(författare)
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A sub-100 nm thickness flat jet for extreme ultraviolet to soft X-ray absorption spectroscopy
- 2024
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Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 31:3 Pt, s. 605-612
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Tidskriftsartikel (refereegranskat)abstract
- Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown.
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| 2. |
- Ilyakov, I., et al.
(författare)
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Terahertz-wave decoding of femtosecond extreme-ultraviolet light pulses
- 2022
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Ingår i: Optica. - : Optica Publishing Group. - 2334-2536. ; 9:5, s. 545-550
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, femtosecond extreme-ultraviolet (XUV) and x-ray pulses from free-electron lasers have developed into important probes to monitor processes and dynamics in matter on femtosecond-time and angstrom-length scales. With the rapid progress of versatile ultrafast x-ray spectroscopy techniques and more sophisticated data analysis tools, accurate single-pulse information on the arrival time, duration, and shape of the probing x-ray and XUV pulses becomes essential. Here, we demonstrate that XUV pulses can be converted into terahertz electromagnetic pulses using a spintronic terahertz emitter. We observe that the duration, arrival time, and energy of each individual XUV pulse is encoded in the waveform of the associated terahertz pulses, and thus can be readily deduced from single-shot terahertz time-domain detection.
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| 3. |
- Maznev, A. A., et al.
(författare)
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Generation and detection of 50 GHz surface acoustic waves by extreme ultraviolet pulses
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:4
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Tidskriftsartikel (refereegranskat)abstract
- We use femtosecond extreme ultraviolet pulses derived from a free electron laser to excite and probe surface acoustic waves (SAWs) on the (001) surface of single crystal SrTiO3. SAWs are generated by a pair of 39.9 nm pulses crossed at the sample with the crossing angle defining the SAW wavelength at 84 nm. Detection of SAWs is performed via diffraction of a time-delayed 13.3 nm probe pulse by SAW-induced surface ripples. Despite the low reflectivity of the sample in the extreme ultraviolet range, the reflection mode detection is found to be efficient because of an increase in the diffraction efficiency for shorter wavelengths. We describe a methodology for extracting the SAW attenuation in the presence of a thermal grating, which is based on measuring the decay of oscillations at twice the SAW frequency. The proposed approach can be used to study ultrahigh frequency SAWs in a broad range of materials and will bridge the wave vector gap in surface phonon spectroscopy between Brillouin scattering and He atom scattering.
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