Lensless Fourier transform holography with soft x-rays

Soft x-rays are effective for viewing nanoscale systems with element-specific contrast. Observations of these systems at sub-picosecond time scales are limited by the currently available x-ray sources, but this will change as x-ray free electron lasers come online. Capturing ultrafast images on the nanoscale at these x-ray sources will require techniques that are compatible with coherent, ultrafast, high-intensity x-ray pulses. Fourier transform holography (FTH) is one such technique.; The developments in lensless soft x-ray FTH that make it a practical technique for single shot imaging are presented in this dissertation. FTH is robust, versatile and well suited for imaging with high spatial resolution. The key to realizing these attributes is the integration of a nanoscale transmission mask with the sample. The mask, which defines the holographic object and reference beams, is fabricated by focused ion beam milling.; The advantages of using the integrated mask were first demonstrated by imaging a non-periodic magnetic worm domain pattern with 50 nm spatial resolution. This demonstration of spectro-holography used x-ray magnetic circular dichroism to capture a high contrast lensless image of the ferromagnetic domain structure in a magnetic multilayer film.; A set of four follow-on experiments have developed the single shot capabilities of FTH. (1) Spatial multiplexing is introduced to extend the effective field of view without compromising spatial resolution. (2) By combining the extended field of view with a cross-beam pump-probe geometry, a method is proposed for imaging ultrafast evolution in a single shot. (3) Multiple reference sources are used experimentally to improve the signal-to-noise ratio of an image without increasing the exposure to the sample. (4) The capability of FTH to simultaneously access both phase and absorption contrast is observed.; Without a laser like source of coherent x-rays, these experiments used high brilliance synchrotron radiation from undulator beamlines on electron storage rings, namely SSRL at SLAC and BESSY in Germany. The new instrumentation and methods developed here are relevant and transferable to the forthcoming x-ray free electron laser sources.