Electron microscopy enables researchers to visualize tiny objects such as viruses, the fine structures of semiconductor devices, and even atoms arranged on a material surface. Focusing down the electron beam to the size of an atom is vital for achieving such high spatial resolution. However, when the electron beam passes through an electrostatic or magnetic lens, the rays of electrons exhibit different focal positions depending on the focusing angle and the beam spreads out at the focus. Correcting this "spherical aberration" is costly and complex, meaning that only a select few scientists and companies possess electron microscopes with atomic resolution.