Jianwei (John) Miao
University of California, Los Angeles
Jianwei (John) Miao is Professor of Physics and Astronomy at UCLA. He pioneered computational microscopy by unifying crystallography with microscopy using coherent diffraction and algorithms, replacing lenses with computation. In 1999, he achieved the first experimental coherent diffractive imaging, laying the foundation for modern ptychography and transforming nanoscale and atomic-scale imaging across synchrotrons, XFELs, HHG, optical microscopy, and electron microscopy. Building on this foundation, he pioneered atomic electron tomography (AET) in 2012 for 3D atomic imaging without crystallinity, and in 2021 reported the first 3D atomic structure of an amorphous solid. He recently advanced ptychographic AET to image individual light atoms in 3D with picometer precision. His honors include the Werner Meyer-Ilse Memorial Award, Sloan Fellowship, MRS’s Innovation in Materials Characterization Award, APS’s Joseph F. Keithley Award for Advances in Measurement Science, and election as APS and MRS Fellow.
Presentation Title:
Computational Microscopy: Coherent Diffractive Imaging and Ptychography
Abstract:
Coherent diffractive imaging (CDI) and ptychography use coherent diffraction and computational phase retrieval to replace the image-forming lens, enabling quantitative microscopy across length scales. In this talk, I will focus on recent advances in X-ray CDI and ptychographic tomography, highlighting how synchrotron radiation and X-ray free-electron lasers enable nondestructive 3D measurements of nanoscale structure, lattice strain, chemical heterogeneity, and vector fields in materials. As a representative example, I will describe soft-X-ray vector ptycho-tomography, which reconstructs the 3D magnetization vector field of a ferromagnetic meta-lattice with 10 nm spatial resolution and reveals topological magnetic monopoles and anti-monopoles and their interactions. I will also briefly discuss ptychographic atomic electron tomography as a complementary development, demonstrating 3D localization of individual light atoms with picometer precision. Finally, I will discuss future opportunities enabled by brighter coherent X-ray sources, advanced detectors, low-dose imaging, time-resolved measurements, and AI-assisted phase retrieval. These advances establish coherent diffraction and computation as a quantitative platform for 3D nanoscale, atomic-scale, and vector-field metrology.
Organization Page
- Fields
- SYM-FALL-2026