TY  - JOUR
A1  - Gorobtsov, O. Yu.
A1  - Mercurio, G.
A1  - Brenner, G.
A1  - Lorenz, Ulf
A1  - Gerasimova, N.
A1  - Kurta, R. P.
A1  - Hieke, F.
A1  - Skopintsev, P.
A1  - Zaluzhnyy, I.
A1  - Lazarev, S.
A1  - Dzhigaev, D.
A1  - Rose, M.
A1  - Singer, A.
A1  - Wurth, W.
A1  - Vartanyants, I. A.
T1  - Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry
JF  - Physical review : A, Atomic, molecular, and optical physics
N2  - We present a comprehensive experimental analysis of statistical properties of the self-amplified spontaneous emission free-electron laser (FEL) FLASH by means of Hanbury Brown and Twiss interferometry. The experiments were performed at FEL wavelengths of 5.5, 13.4, and 20.8 nm. We determined the second-order intensity correlation function for all wavelengths and different operation conditions of FLASH. In all experiments a high degree of spatial coherence (above 50%) was obtained. Our analysis performed in spatial and spectral domains provided us with the independent measurements of an average pulse duration of the FEL that were below 60 fs. To explain the complicated behavior of the second-order intensity correlation function we developed an advanced theoretical model that includes the presence of multiple beams and external positional jitter of the FEL pulses. By this analysis we determined that in one of the experiments external positional jitter was about 25% of the beam size. We envision that methods developed in our study will be used widely for analysis and diagnostics of FEL radiation.
Y1  - 2017
U6  - https://doi.org/10.1103/PhysRevA.95.023843
SN  - 2469-9926
SN  - 2469-9934
VL  - 95
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Dzhigaev, D.
A1  - Shabalin, A.
A1  - Stankevic, T.
A1  - Lorenz, Ulf
A1  - Kurta, R. P.
A1  - Seiboth, F.
A1  - Wallentin, J.
A1  - Singer, A.
A1  - Lazarev, S.
A1  - Yefanov, O. M.
A1  - Borgstrom, M.
A1  - Strikhanov, M. N.
A1  - Samuelson, L.
A1  - Falkenberg, G.
A1  - Schroer, C. G.
A1  - Mikkelsen, A.
A1  - Vartanyants, I. A.
T1  - Bragg coherent x-ray diffractive imaging of a single indium phosphide nanowire
JF  - Journal of optics
N2  - Three-dimensional (3D) Bragg coherent x-ray diffractive imaging (CXDI) with a nanofocused beam was applied to quantitatively map the internal strain field of a single indium phosphide nanowire. The quantitative values of the strain were obtained by pre-characterization of the beam profile with transmission ptychography on a test sample. Our measurements revealed the 3D strain distribution in a region of 150 nm below the catalyst Au particle. We observed a slight gradient of the strain in the range of +/- 0.6% along the [111] growth direction of the nanowire. We also determined the spatial resolution in our measurements to be about 10 nm in the direction perpendicular to the facets of the nanowire. The CXDI measurements were compared with the finite element method simulations and show a good agreement with our experimental results. The proposed approach can become an effective tool for in operando studies of the nanowires.
KW  - Bragg coherent x-ray diffractive imaging
KW  - InP nanowires
KW  - strain field
Y1  - 2016
U6  - https://doi.org/10.1088/2040-8978/18/6/064007
SN  - 2040-8978
SN  - 2040-8986
VL  - 18
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -