title: Octave-spanning hyperspectral coherent diffractive imaging in the extreme ultraviolet range.
abstract: Soft x-ray microscopy is a powerful imaging technique that provides sub-micron spatial resolution, as well as chemical specificity using core-level near-edge x-ray absorption fine structure (NEXAFS). Near the carbon K-edge (280-300 eV) biological samples exhibit high contrast, and the detailed spectrum contains information about the local chemical environment of the atoms. Most soft x-ray imaging takes place on dedicated beamlines at synchrotron facilities or at x-ray free electron laser facilities. Tabletop femtosecond laser systems are now able to produce coherent radiation at the carbon K-edge and beyond through the process of high harmonic generation (HHG). The broad bandwidth of HHG is seemingly a limitation to imaging, since x-ray optical elements such as Fresnel zone plates require monochromatic sources. Counter-intuitively, the broad bandwidth of HHG sources can be beneficial as it permits chemically-specific hyperspectral imaging. We apply two separate techniques - Fourier transform spectroscopy, and lensless holographic imaging - to obtain images of an object simultaneously at multiple wavelengths using an octave-spanning high harmonic source with photon energies up to 30 eV. We use an interferometric delay reference to correct for nanometer-scale fluctuations between the two HHG sources.
authors.forename: Yijian
authors.initials: Y
authors.lastname: Meng
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhang
authors.forename: Claude
authors.initials: C
authors.lastname: Marceau
authors.forename: A Yu
authors.initials: AY
authors.lastname: Naumov
authors.forename: P B
authors.initials: PB
authors.lastname: Corkum
authors.forename: D M
authors.initials: DM
authors.lastname: Villeneuve