Dresden 2014 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 6: X-ray Imaging, Holography and Tomography

MI 6.2: Vortrag

Mittwoch, 2. April 2014, 11:15–11:30, MER 02

High resolution coherent diffractive imaging with a table-top high harmonic source — •Sergey Zayko¹, Eike Mönnich¹, Murat Sivis¹, Tobias Mey³, Dong-Du Mai², Klaus Mann³, Tim Salditt², and Claus Ropers¹ — ¹1IV. Institute of Physics, University of Göttingen, Germany — ²Institute for X-Ray Physics, University of Göttingen, Germany. — ³Laser Laboratorium Göttingen, Germany

High harmonic up-conversion of femtosecond laser pulses allows for the generation of coherent extreme ultraviolet radiation from table-top devices. Here, we present a study of coherent diffractive imaging (CDI) using high harmonic generation at a wavelength of 34.7 nm using amplified 800 nm femtosecond laser pulses. The setup employs a toroidal grating monochromator in order to carry out diffraction-limited CDI at a reduced spectral bandwidth. Diffraction images for several lithographically prepared objects were recorded, and successful object reconstructions were obtained by means of iterative phase retrieval algorithms. Resolutions of 38 nm and 34 nm are achieved for a single exposure of 5 s and accumulating multiple exposures, respectively, corresponding to the maximum achievable resolution given by the numerical aperture of the detection setup. Reconstructions for objects up to about 10 micrometres diameter were performed, presently limited by the transverse coherence length of the incident wavefront, which was independently characterized. A further increase of the photon flux and a reduction of the exposure times will be reached by utilizing 400 nm pump pulses, and the spatial resolution will be improved by the use of shorter harmonic wavelengths.