Using Light to Control Material Functionality

Material functionality is governed not only by chemical composition, but also by the interactions and symmetries that constrain its response. Engineered electromagnetic environments offer a route to modify these interactions through light–matter coupling, where photonic modes hybridize with material excitations to form new states with properties distinct from those of their uncoupled constituents. Here, we ask whether light–matter coupling can also modify symmetry-constrained material responses. We address this question using the bulk photovoltaic effect, a nonlinear photoresponse governed by crystal symmetry, in a centrosymmetric material coupled to a photonic mode resonant with its excitons. By probing the photovoltaic response of the hybrid system, we explore whether coupling can reshape the symmetry constraints governing its functionality. More broadly, this work points toward engineered light–matter coupling as a tool for controlling electrical, nonlinear, and transport properties of materials.