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تسجيل مستخدم جديدDiffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser
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We demonstrate experimentally Hanbury Brown and Twiss (HBT) interferometry at a hard X-ray Free Electron Laser (XFEL) on a sample diffraction patterns. This is different from the traditional approach when HBT interferometry requires direct beam measurements in absence of the sample. HBT analysis was carried out on the Bragg peaks from the colloidal crystals measured at Linac Coherent Light Source (LCLS). We observed high degree (80%) spatial coherence of the full beam and the pulse duration of the monochromatized beam on the order of 11 fs that is significantly shorter than expected from the electron bunch measurements.
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We present measurements of second- and higher-order intensity correlation functions (so-called Hanbury Brown and Twiss experiment) performed at the free-electron laser (FEL) FLASH in the non-linear regime of its operation. We demonstrate the high tra
nsverse coherence properties of the FEL beam with a degree of transverse coherence of about 80% and degeneracy parameter of the order 10^9 that makes it similar to laser sources. Intensity correlation measurements in spatial and frequency domain gave an estimate of the FEL average pulse duration of 50 fs. Our measurements of the higher-order correlation functions indicate that FEL radiation obeys Gaussian statistics, which is characteristic to chaotic sources.
We present a comprehensive experimental analysis of statistical properties of the self-amplified spontaneous emission (SASE) free-electron laser (FEL) FLASH at DESY in Hamburg by means of Hanbury Brown and Twiss (HBT) interferometry. The experiments
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We show that the essential physics of the Hanbury Brown-Twiss (HBT) and the thermal light ghost imaging experiments is the same, i.e., due to the intensity fluctuations of the thermal light. However, in the ghost imaging experiments, a large number o
f bits information needs to be treated together, whereas in the HBT there is only one bit information required to be obtained. In the HBT experiment far field is used for the purpose of easy detection, while in the ghost image experiment near (or not-far) field is used for good quality image.
We report measurements of Hanbury Brown and Twiss correlation of coherent light transmitted through disordered one-dimensional photonic lattices. Although such a lattice exhibits transverse Anderson localization when a single input site is excited, u
niform excitation precludes its observation. By examining the Hanbury Brown--Twiss correlation for a uniformly excited disordered lattice, we observe intensity anticorrelations associated with photon antibunching--a signature of non-Gaussian statistics. Although the measured average intensity distribution is uniform, transverse Anderson localization nevertheless underlies the observed anticorrelation.
Second-order intensity interferometry was employed to study the spatial and temporal properties of the European X-ray Free-Electron Laser (EuXFEL). Measurements were performed at the soft X-ray SASE3 undulator beamline at a photon energy of 1.2 keV i
n the Self-Amplified Spontaneous Emission (SASE) mode. Two high-power regimes of the SASE3 undulator settings, i.e. linear and quadratic tapering at saturation, were studied in detail and compared with the linear gain regime. The statistical analysis showed an exceptionally high degree of spatial coherence up to 90% for the linear undulator tapering. Analysis of the measured data in spectral and spatial domains provided an average pulse duration of about 10 fs in our measurements. The obtained results will be valuable for the experiments requiring and exploiting short pulse duration and utilizing high coherence properties of the EuXFEL.
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