Spatially resolved soft X-ray spectrometry from single-image diffraction

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Abstract

High-harmonic generation (HHG) offers better coherence1, shorter pulse durations2 and far greater accessibility than synchrotron sources3. These factors make HHG an increasingly important source of soft X-rays and an excellent resource in many emerging areas, for example, the time-resolved study of conformational changes in single biological molecules4. Here, we demonstrate a novel technique that enables us to reconstruct spectral information spatially across an X-ray beam. As only a single diffraction image is required per measurement, this technique is well suited to time-resolved studies. This technique is applicable to many types of X-ray source3,5,6,7 and can be adapted for different spectral regions. Here, results are obtained using a capillary high-harmonic source8, revealing detailed information that brings new insight into the physical processes occurring inside the source and enabling us to show the first measurement of radial variation of harmonic order in the emission from an HHG capillary.

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Figure 1: Measured diffraction pattern for an argon pressure of 80 mbar.
Figure 2: High-harmonic X-ray spectra for argon in a capillary.
Figure 3: An example of the spatially resolved reconstructed spectrum.
Figure 4: Transverse spatial intensity profile as a function of harmonic order.

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Acknowledgements

This work was supported by the UK Research Councils through the Basic Technology Programme.

Author information

Experimental work: M.P., A.M.dP., C.A.F., S.L.S. Data analysis: M.P., E.T.R., W.S.B., J.J.B. Writing: M.P., A.M.dP., C.A.F., E.T.R., S.L.S., W.S.B., J.J.B., D.C.H., J.G.F. Project planning: W.S.B., J.J.B., D.C.H., J.G.F.

Correspondence to M. Praeger.

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The authors declare no competing financial interests.

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Praeger, M., de Paula, A., Froud, C. et al. Spatially resolved soft X-ray spectrometry from single-image diffraction. Nature Phys 3, 176–179 (2007) doi:10.1038/nphys516

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