Abstract: A well-motivated class of dark matter candidates, including axion-like particles and dark photons, takes the form of coherent oscillations of a light bosonic field. If the dark matter couples to Standard Model photons, it may be possible to detect it via absorptions in a laboratory target. I will discuss a new class of detectors at frequencies from the infrared through the ultraviolet, based on spatially periodic dielectrics. In these photonic materials, bosonic dark matter can efficiently convert to detectable single photons. With current experimental techniques, these detectors can probe significant new parameter space for axion and dark photon dark matter in the 0.1 − 10 eV mass range; a prototype is currently being implemented.