Grant van Riessen's research interests lie in the areas of experimental condensed matter physics and coherent X-ray diffractive imaging development. He leads a program of research that aims to develop soft X-ray coherent diffractive imaging and spectroscopy methods for in situ and in operando study of magnetic and functional materials.This work is done in close collaboration with researchers at the Australian Synchotron, where his group operates a dedicated soft X-ray imaging endstation. The group also uses modern methods of numerical simulation and nanofabrication to optimise and fabricate X-ray optics and novel synchrotron instrumentation.

Grant also studies the dynamics of photoexcitation and decay using two-electron coincidence spectroscopy.The work is currently focused on the study of electron correlation effects at surfaces and buried interfaces using soft X-ray induced photoemission-Auger processes. This work builds upon similar studies of double photoemission and electron and positron induced electron pair emission.