Circularly Polarized Soft X-Ray High Harmonics and XMCD on a Tabletop

2015 ◽  
Author(s):  
Tingting Fan ◽  
Patrik Gychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel Hickstein ◽  
...  
Keyword(s):  
Circularly Polarized ◽  
X Ray ◽  
High Harmonics

scholarly journals Bright Circularly Polarized Soft X-Ray High Harmonics for X-Ray Magnetic Circular Dichroism

2015 ◽  
Author(s):  
Tingting Fan ◽  
Patrik Gychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel Hickstein ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Circularly Polarized ◽  
X Ray ◽  
High Harmonics ◽  
Circular Dichroïsm

scholarly journals Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

2015 ◽  
Vol 112 (46) ◽  
pp. 14206-14211 ◽  
Author(s):  
Tingting Fan ◽  
Patrik Grychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel D. Hickstein ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Single Atom ◽  
Phase Matching ◽  
Electromagnetic Spectrum ◽  
Conservation Of Energy ◽  
Circularly Polarized ◽  
X Ray ◽  
High Harmonics ◽  
Circular Dichroïsm

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

In Situ Magnetic-Circular-X-Ray-Dichroism Measurements: An Epitaxial Fe Wedge on Cu(100)

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 41-45 ◽  
Author(s):  
M.E. Dávila ◽  
D. Arvanitis ◽  
J. Hunter Dunn ◽  
N. Mårtensson ◽  
P. Srivastava ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Magnetic Circular Dichroism ◽  
Polarized Light ◽  
Measured Quantity ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Core Electron ◽  
Circularly Polarized ◽  
X Ray

Circularly polarized x-ray radiation is attracting increasing interest as a tool for the characterization of the electronic, magnetic, and chiral properties of low-dimensional structures. Using circular light (with electric field vector parallel to the orbital plane), a dependence of the measured quantity by changing either the orientation of the light polarization or the magnetization is indicative of the existence of magnetic circular dichroism. It can be observed in x-ray absorption spectroscopy (XAS), in which the photon energy is scanned through an absorption threshold exciting a core electron into an unoccupied valence state using circularly polarized light. Synchrotron radiation sources have made this technique possible. It can also be observed in photo-emission spectroscopy from core and valence levels. Here we focus on magnetic circular x-ray dichroism (MCXD) in XAS as an element-specific tool to investigate magnetic properties of ultrathin films in situ. The application of magneto-optical sum rules enables the determination of the orbital and spin magnetic moments per atom from XAS spectra, as well as the easy magnetization direction.MCXD-based magnetometry in XAS is extensively used by measuring the L absorption edges of 3d-transition metals, where large intensity changes (up to 60%) of the L-edge white lines are observed upon reversal of either the sample magnetization or the light helicity. The high magnetic contrast obtained, combined with the elemental specificity of the technique, allows for the study of very dilute samples such as ultrathin films. We first concentrate on the selection rules governing MCXD in XAS.

The determination of crystal size and disorder from X-ray diffraction photographs of polymer fibres. 1. The accuracy of determination of Fourier coefficients of the intensity profile of a reflection

1989 ◽  
Vol 22 (4) ◽  
pp. 363-371 ◽  
Author(s):  
R. Somashekar ◽  
I. H. Hall ◽  
P. D. Carr
Keyword(s):  
Crystal Size ◽  
Fourier Coefficients ◽  
Intensity Profile ◽  
X Ray Diffraction ◽  
Scattering Angle ◽  
X Ray ◽  
Fourier Cosine ◽  
High Harmonics ◽  
Lattice Planes

Methods which determine the number and disorder of lattice planes in a crystal from the Fourier cosine coefficients of the intensity profile of an X-ray reflection use only the low harmonics and require that the coefficients be normalized so that the zero harmonic is unity. Experimentally, the profiles can only be recorded over a smaller range of scattering angle than required by the theory, and it is necessary to subtract background, which is likely to be estimated with considerable error, before determining the coefficients. It is shown that with polymer fibres this causes serious errors in the normalization, and in the values of those low harmonics used in the size and disorder determination, and prevents reliable values being obtained. Methods which avoid normalization and use only high harmonics are needed. It is shown that disorder may be obtained in such a way, but not size, for which low-order normalized coefficients are essential. A method of extrapolation is described and tested which enables the accurate high harmonics to be used to improve the estimates of the low ones. Whilst this will yield more reliable values of crystal size than are obtainable from existing methods, the accuracy depends entirely on the validity of the extrapolation, which cannot be tested in many cases of interest.

Generation of Bright Circularly-Polarized High Harmonics for Magneto-Optical Investigations

2015 ◽  
pp. 187-192
Author(s):  
P. Grychtol ◽  
O. Kfir ◽  
R. Knut ◽  
E. Turgut ◽  
D. Zusin ◽  
...  
Keyword(s):  
Circularly Polarized ◽  
High Harmonics

First experimental evidence of circularly polarized X-ray excited optical luminescence (XEOL) from chiral Eu3+ complexes

1990 ◽  
Vol 147 (1) ◽  
pp. 165-172 ◽  
Author(s):  
Christophe Gauthier ◽  
Isabella Ascone ◽  
José Goulon ◽  
Robert Cortes ◽  
Jean-Michel Barbe ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Circularly Polarized ◽  
X Ray ◽  
Optical Luminescence

Magnetic Microscopy Using a Circularly Polarized Hard-X-ray Nanoprobe at SPring-8

2020 ◽  
Vol 33 (2) ◽  
pp. 4-11
Author(s):  
M. Suzuki ◽  
H. Yumoto ◽  
T. Koyama ◽  
H. Yamazaki ◽  
T. Takeuchi ◽  
...  
Keyword(s):  
Circularly Polarized ◽  
X Ray ◽  
Magnetic Microscopy

Influence of higher harmonics of the undulator in X-ray polarimetry and crystal monochromator design

2015 ◽  
Vol 22 (5) ◽  
pp. 1151-1154 ◽  
Author(s):  
Berit Marx-Glowna ◽  
Kai S. Schulze ◽  
Ingo Uschmann ◽  
Tino Kämpfer ◽  
Günter Weber ◽  
...  
Keyword(s):  
Multiple Reflection ◽  
Higher Harmonics ◽  
Undulator Radiation ◽  
X Ray ◽  
High Harmonics ◽  
Even Harmonics

The spectrum of the undulator radiation of beamline P01 at Petra III has been measured after passing a multiple reflection channel-cut polarimeter. Odd and even harmonics up to the 15th order, as well as Compton peaks which were produced by the high harmonics in the spectrum, could been measured. These additional contributions can have a tremendous influence on the performance of the polarimeter and have to be taken into account for further polarimeter designs.

Observation of selection rules for circularly polarized high harmonics from a solid

2018 ◽  
Author(s):  
Nariyuki Saito ◽  
Peiyu Xia ◽  
Faming Lu ◽  
Nobuhisa Ishii ◽  
Teruto kanai ◽  
...  
Keyword(s):  
Selection Rules ◽  
Circularly Polarized ◽  
High Harmonics
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