UC Berkeley

The interaction of electrons with an electromagnetic field is one of the most important phenomena in physics. The electromagnetic interaction is central to the absorption and emission of light by matter and permits interpretation of physical phenomena in our natural world. This dissertation uses light-matter interactions to probe the behavior of electrons in atomically thin materials and to develop new scientific tools for the study of intermolecular dynamics.

In Part I, we present and demonstrate a set of principles that permit the rational design of two dimensional covalent organic frameworks with optical and electronic properties not present in their constituent counterparts. We develop a novel low bandgap framework that is characterized under broadband optical spectroscopy, X-ray scattering, transmission electron microscopy, atomic force microscopy, and transport. In inorganic/organic van der Waals heterostructures, we report ultrafast electron dynamics not previously observed in two dimensional covalent organic frameworks with consequences that are relevant to a broad range of materials.

In Part II, we manipulate light-matter interactions in atomically thin materials to develop an optical sensor capable of imaging electric fields generated by intermolecular dynamics. We combine the unique gate-variable optical transitions in graphene with critically-coupled waveguide amplification to convert electrical activity into optical signals while retaining high spatio-temporal resolution. We apply this technique to living systems and noninvasively image signals from and among electrically active cells.