Coherent diffractive imaging with laboratory scale EUV sources

Odstrčil, M., Baksh, P., Kim, H., Brocklesby, W.S. and Frey, J.G. (2016) Coherent diffractive imaging with laboratory scale EUV sources. EXTATIC Welcome Week, Southampton, United Kingdom. 11 - 15 Jan 2016.

Abstract

The ptychography method for coherent diffractive imaging (CDI) is gaining significant popularity over the last few years in the synchrotron science community because of its advantages over simpler single diffraction CDI schemes. However, for imaging applications in the extreme ultraviolet (XUV), the ability to perform ptychography with table top setups is limited by requirements on high coherence of illumination and overall beam quality. With the aim of improving imaging using coherent table-top EUV sources, we demonstrate that high harmonics generation (HHG) source at 29 nm wavelength with relative bandwidth (Delta.lambda/lambda) of ~15% can provide useful gain in available flux without deteriorating the reconstruction quality. The HHG spectrum was self-consistently measured by the Young double slit (Fourier) based EUV spectrometer using the same setup that used for ptychography. Our setup uses fewer monochromating optics, obtaining higher flux at the sample and thus reaching higher resolution for semi-opaque objects. High coherent photon flux density is more critical in the case of ptychography when a large number of diffraction patterns needs to be collected compared to the traditional coherent diffraction method with compactness constraints. Our improved reconstruction method was tested on an aperiodic grid sample with reconstructed area 40×40 µm and half period resolution 55 nm but also on natural samples consisting from dried neurons on a 50nm thick silicon nitride window with 90nm resolution.

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Contributors

Author: W.S. Brocklesby

Author: J.G. Frey

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