Researchers have found a new way to image layers of boron nitride that are only a single atom thick. This material is usually nearly invisible in optical microscopes because it has no optical resonances. To resolve this issue, the team uses nonlinear microscopy with infrared light, making the material shine very brightly and even reveal its crystal orientation. The work has important implications for the vibrant field of designing new (opto-)electronic devices from stacking 2D materials.
