Conventional and propagation-based phase contrast imaging of nanostructures using femtosecond laser driven cluster plasma source and lif crystal soft x-ray detectors

Abstract

Bright source of soft X-ray emission was developed. Soft X-ray radiation was produced by femtosecond laser pulses irradiation of submicron size CO2 clusters. These clusters were produced in custom designed supersonic nozzle from the mixture of the 10% CO2 + 90 % He expanding gases. Lithium fluorine based soft X-ray detectors was used for registration of absorption images of ultrathin (nanoscale) foils and biological structures illuminated by the developed source. It was demonstrated that even if the foil is essentially transparent for the soft X-ray radiation (like 100 nm thick Zr foil), the image contrast could be significantly increased due to the influence of propagation-based phase-contrast effect when detector is placed at the proper distance behind the sample. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.