Coherent Imaging of Quantum Solids Using a Computer-Generated Hologram

• Applicant: Dr. Kahraman Keskinbora, Ph.D.
• Subject Area: Experimental Condensed Matter Physics ; Coating and Surface Technology ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 428809035

Powerful imaging methods open new windows to the micro/nano-world, fuelling the miniaturization trend accompanied by an explosion in our technology. To overcome environmental impacts of this unprecedented growth, we need new low-power computing and efficient clean energy technologies contingent upon development of novel materials. Recently, X-ray microscopy emerged as an ideal tool to embrace such materials research opportunities to address modern societal challenges. This project aims to develop a new X-ray holography method to investigate quantum solids at the nanoscale. Our goal is to visualize microscopic textures that underlie the macroscopic quantum behavior of such materials. The technique depends on computer-generated holograms to split the incident X-rays into a reference beam and a sample beam. The reference beam propagates in the vacuum while the sample beam traverses the sample and is imprinted with phase information that encodes the internal electronic and magnetic structure of the specimen. A camera then captures the interference pattern from which a complex-valued image of the sample is recovered with a spatial resolution down to <30 nm. The image carries information about the samples’ properties such as composition, density, and magnetization. The proposed method has several key advantages: (i) the sample and reference beams are not defined by pre-patterned structures, avoiding the time-consuming sample preparation; (ii) The field of view is not physically anchored to a pre-selected region, allowing investigation of extended samples; (iii) The separation of the sample and the illumination allows vastly flexible experimental capabilities such as reflection geometry with new possibilities; (iv) The approach is compatible with single-shot, ultra-fast imaging at the nanoscale. Simulations support the viability of the proposed method we call the Structured Illumination X-ray Holography (SIXH). SIXH will provide new insights in X-ray microscopy, but more importantly, it critically leverages current and future high-coherence sources. Therefore, it is poised to have a broad impact on our understanding of quantum solids and X-ray science in general, with far-reaching applications extending beyond hard condensed matter physics.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Riccardo Comin