Novel X-Ray Imaging Systems Enabled by Nanofabrication

X-ray imaging accounts for the majority of medical diagnostic procedures in the United States. Rapidly increasing utilization of x-ray imaging, especially computed tomography (CT), has led to major concerns about the population radiation dose. Enhancing the sensitivity of x-ray imaging systems results in a proportional reduction of the radiation dose, which has attracted a great deal of attention. This talk presents our recent development of an ultra-sensitive x-ray interferometric imaging system enabled by nanofabrication. The development of cost-effective processes to fabricate deep submicron period hard x-ray diffraction gratings will be described. Then special focus will be given to the invention of an x-ray polychromatic far-field interferometer with the fabricated gratings, where preliminary experiments demonstrated more than an order of magnitude improvement of the sensitivity compared to the state-of-the-art grating-based interferometry technique. Potential application of the far-field interferometer in digital mammography will be discussed. A universal moiré effect to explain the physics of the polychromatic far-field interferometer and the application of this fundamental optical effect in neutron imaging will be presented.