Imaging objects at nanometer resolution is a significant challenge since the achievable resolution in a microscope is limited to approximately half of the wavelength of the illuminating light. This limits the resolution of an optical microscope to few hundred nanometers. We push these limits by applying short-wavelength (extreme ultraviolet and soft X-ray) light sources for high-resolution imaging. The coherent nature of our sources allows us to employ a scheme called coherent diffraction imaging, where a detector directly measures the diffracted X-rays. Using advanced computer algorithms we perform the actual imaging in the computer by inverting the measured diffraction pattern by solving the so-called phase problem. Extending this method by raster-scanning an object, which is called ptychography, we can retrieve nanoscale images with a literally infinite field of view and with high fidelity.
In our lab we strive for combining aspects of ptychograpahy and time-resolved spectroscopy to resolved nanoscale dynamics.
G. K. Tadesse, W. Eschen, R. Klas, M. Tschernajew, F. Tuitje, M. Steinert, M. Zilk, V. Schuster, M. Zürch, T. Pertsch, C. Spielmann, J. Limpert, J. Rothhardt. Wavelength-scale ptychographic coherent diffractive imaging using a high-order harmonic source, Scientific Reports 9, 1735 (2019)
T. Helk, M. Zürch , and C. Spielmann. Towards single shot timeresolved microscopy using short wavelength table-top light sources, Structural Dynamics 6, 010902 (2019)
M. Zürch, R. Jung, C. Spaeth, J. Tümmler, A. Guggenmos, D. Attwood, U. Kleineberg, H. Stiel and C. Spielmann. Spatial Coherence Limited Coherence Diffraction Imaging using a Molybdenum Soft X-ray Laser Pumped at Moderate Pump Energies, Nature Scientific Reports 7:5314, 1-10 (2017)
G.K. Tadesse, R. Klas, S. Demmler, S. Hädrich, I. Wahyutama, M. Steinert, C. Spielmann, M. Zürch, T. Pertsch, A. Tünnermann, J. Limpert and J. Rothhardt. High speed and high resolution table-top nanoscale imaging, Optics Letters 41 (22), 5170-5173 (2016)
M. Zürch and C. Spielmann. Extreme ultraviolet digital in-line holography using a table top source, Applied Optics 54 (19), 5992-5997 (2015)
M. Zürch, J. Rothhardt, S. Hädrich, S. Demmler, M. Krebs, J. Limpert, A. Tünnermann, A. Guggenmos, U. Kleineberg, and C. Spielmann. Real-time and Sub-wavelength Ultrafast Coherent Diffraction Imaging in the Extreme Ultraviolet, Nature Scientific Reports 4 (7356), 1-5 (2014)
M. Zürch, C. Kern, and Ch. Spielmann. XUV coherent diffraction imaging in reflection geometry with low numerical aperture, Optics Express 21 (18), 21131-21147 (2013)