Ultrastable XUV interferometry for broadband lensless imaging

Lensless imaging is the technique of numerically reconstructing an image of a sample instead of imaging the sample on the camera using lenses. This is an interesting solution for microscopy with extreme ultraviolet (XUV) and X-ray radiation, as good-quality lenses for this type of radiation are lacking. Most lensless imaging techniques require the use of monochromatic light and therefore suffer from low flux when implemented using table-top high-harmonic generation (HHG) sources. We recently introduced a broadband lensless imaging method inspired by Fourier transform spectroscopy, in which we illuminate the sample using two identical phase-locked pulses and record the resulting diffraction pattern on a CCD camera (see figure 1) [1,2]. By scanning the delay between the pulses and recording the diffraction patterns, it is possible to reconstruct the scattered spectrum for every pixel on the detector. This data enables the selection of monochromatic diffraction patterns for every wavelength available in the pulses. It is then possible to do image reconstruction using this data, for all wavelengths in the HHG source spectrum.