William and his research team seek to build novel photonic devices by leveraging nanoscale structures to control the interaction between electrons and photons. An overarching theme of their research is making “big science” small; specifically, his group is using innovative photonic structures and laser systems to work towards building table-top particle accelerators, compact free-electron lasers (FELs), and chip-scale laboratories for strong-field laser physics. Such compact accelerators and FELs, as well as chip-scale strong-field devices, are promising for a wide-range of scientific, medical and industrial applications.