The formulation of quantum mechanics in the late 1920s forever changed physics. More recently, quantum materials have emerged, offering fascinating opportunities in condensed matter physics. Elementary interactions among elements such as electrons, phonons, and other quasiparticles in quantum materials give rise to the emergence of intriguing phases and offer enormous opportunities for the development of quantum technologies. But investigating these interactions at the relevant length scale requires high-resolution methods.

Traditional far-field optical imaging and spectroscopy techniques are constrained by the diffraction limit of light. Interestingly, during the same period in the late 1920s, a visionary scientist named Synge introduced a groundbreaking concept that could circumvent the diffraction limit. Synge shared his idea with Einstein, who encouraged him to publish it. After many years of various pioneering works by different groups, a powerful modern nano-optical technique, a variant of Synge's original idea, was born.

In this talk, Yohannes Abate of the University of Georgia will introduce this technique and give examples of high-resolution probing of nanoscale physical phenomena and interactions in two classes of quantum materials: correlated oxides and van der Waals (vdW) crystals.