For a long time, sub-angstrom electron microscopic resolution has been confined to aberration-corrected electron microscopes, which are powerful tools for understanding the atomic structure and properties of matter. Recently, Kayla X. Nguyen, Chia-Hao Lee, Pinshane Y. Huang from the University of Illinois Urbana-Champaign, Yi Jiang from Argonne National Laboratory, and others published a paper in *Science*, reporting electron coherent diffraction imaging in an uncorrected scanning transmission electron microscope (STEM). Its deep sub-angstrom spatial resolution is as low as 0.44 angstroms, exceeding the conventional resolution of aberration-correction tools and comparable to their highest image resolution. In widely used commercial microscopes, two-dimensional twisted materials were demonstrated, far surpassing the previous uncorrected STEM resolution (1 to 5 angstroms). It was further shown how geometric aberrations can create optimized structured beams for dose-efficient electron imaging. The study indicates that expensive aberration correctors are no longer necessary for deep sub-angstrom resolution. Entering the World of Attoseconds An attosecond is a unit of time, where 1 attosecond = 10^-18 seconds. What does this mean? The number of attoseconds in one second is the same as the number of seconds since the birth of the universe. More specifically, it takes tens of billions of attoseconds for a beam of light to travel from one end of an ordinary-sized room to the wall at the other end. In a vacuum, light can travel a distance of approximately 0.3 nanometers in one attosecond. A small hummingbird can flap its wings 80 times per second, and to the human eye, the hummingbird's wings appear as a blurred shadow. To obtain a photo of a hummingbird's wings in flight, high-speed photography and matching lighting technology are required. Similarly, in the microscopic world, when electrons move between atoms, their positions and energies change on an attosecond time scale. To probe the movement state of electrons and "film" them, attosecond laser pulses are indispensable. An attosecond laser pulse is a flash with a duration on the attosecond scale. Its emergence has opened a new door to the microscopic world, meaning that people's ability to study the structure of matter has reached a new level, and the field of basic physics research has thus set off a new trend. Currently, attosecond pulses may bring some转机 to the "dark clouds" floating over the edifice of physics. Breaking the Resolution Limit of Optical Microscopy Ptychography technology achieving resolution below 0.5 angstroms (0.05 nanometers) without correction! The spatial resolution of electron microscopes has long been limited by the inherent aberrations of magnetic lenses. This characteristic has driven the development and application of aberration-corrected electron microscopes, in which electromagnetic components are combined in series to correct lens aberrations. For more than two decades, aberration correctors have enabled sub-angstrom resolution in transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM), making them powerful tools for understanding the atomic structure and properties of matter. However, aberration-corrected microscopes are expensive and complex in structure, requiring a high level of professional knowledge to operate and maintain, which limits the widespread use of sub-micron microscopes. Ptychography provides an alternative approach for high-resolution imaging. Convergent-beam electron diffraction (CBED) patterns are collected as a function of probe position, resulting in a four-dimensional scanning transmission electron microscopy (4D-STEM) dataset. Electron ptychography then solves the phase problem by using overdetermined information in the 4D-STEM data to simultaneously determine the object and the probe. Thus, ptychography eliminates aberrations computationally rather than using lens optics. This feature makes super-resolution imaging possible. Recently, electron ptychography has achieved sub-angstrom resolution (<0.5 Å). However, even with ptychography, uncorrected electron microscopes have not yet reached sub-angstrom resolution. Against this background, the team of Pinshane Huang (recipient of the 2018 Sloan Research Fellowship, a Nobel Prize indicator) from the University of Illinois Urbana-Champaign developed an electron ptychography technique in an uncorrected scanning transmission electron microscope (STEM) by extending data collection to electrons with large momentum scattering and considering the partial coherence of the probe. This technique achieves a higher spatial resolution of 0.44 Å, exceeding the traditional resolution of aberration-correction tools and comparable to their highest ptychographic resolution. The authors demonstrated observational results on a twisted tungsten diselenide bilayer sample in a widely used commercial microscope, proving that the imaging resolution of this method far surpasses the previous ptychographic resolution of uncorrected STEM (1 to 5 Å). The work was published in the latest issue of *Science* under the title "Achieving sub-0.5-angstrom–resolution ptychography in an uncorrected electron microscope". This work reports that high-quality, sub-angstrom resolution imaging can be achieved using only an uncorrected STEM through ptychography. Uncorrected microscopes are less costly, more accessible than aberration-corrected tools, and more compatible with in-situ methods. Almost any scanning transmission electron microscope can adopt this method to achieve sub-angstrom resolution. In addition, this method is compatible with energy technologies in the field of electron ptychography, including multi-layer ptychography and the measurement of electric and magnetic fields, which may expand its application range. Finally, this work proposes a simple method to create structured probes optimized for dose-efficient ptychography, which is expected to facilitate the development of new technologies for low-dose and 3D imaging based on ptychography. Sources: Yunnan Association for Science and Technology, New Materials Today, Frontiers of Polymer Science