Table-top soft x-ray lasers based on high-order harmonic generation (HHG)

Table-top soft x-ray lasers based on high-order harmonic generation (HHG) deliver routinely linearly polarized light. Many advanced applications including magnetic imaging would profit from a HHG source delivering in addition circular polarized light. In one of our recent work we present now an approach which provides intense soft x-ray radiation of high ellipticity. This source has given us the opportunity to realize the first magnetic dichroism experiment on a nickel sample at 18 nm (67 eV) with a table-top HHG source. So far this type of experiment could only be done at large research facilities, such as synchrotrons and free electron lasers. Compared to those our compact laboratory-size harmonic source offers substantially enhanced temporal resolution (a few fs) and virtually jitter-free pump-probe configurations. Our results achieved together with our French collaborators at LOA were recently published in Nature Communications Nature Communications 6, 7167 (2015)