Holographic soft X-ray omni-microscopy of biological specimens.

Mask-based digital soft X-ray Fourier transform holography using coherent synchrotron radiation is applied to image diatoms and freeze-dried 3T3 fibroblast cells. At soft X-ray wavelengths between 4 nm and 8 nm we achieve spatial resolutions down to 450 nm over a 33.5 microm field of view. As holography records amplitude and phase of the scattered wavefield, images with different contrast mechanisms can be generated a posteriori by numerical processing of the holographic data ("omni-microscopy"). We present Zernike phase contrast, Schlieren phase contrast, differential interference and gradient contrast images based on amplitude and phase information. We discuss the potential of this approach for destructive single-shot imaging beyond dose limitations of biological samples at coherent femtosecond-pulsed X-ray sources.