Abstract: An attractive class of dark matter candidates, including axion-like particles and dark photons, take the form of coherent oscillations of a light bosonic field. If these couple Standard Model particles, they may be detectable by coherent absorption in laboratory targets. Current experiments of this kind include cavity-based resonators such as ADMX, operating at microwave frequencies. We propose a class of detectors, ‘photonic helioscopes’, which could probe larger dark matter masses, corresponding to masses around an eV.  I will discuss this proposal to use spatially periodic dielectric materials to search for such bosonic dark matter. Optical structures similar to antireflective coatings can give efficient conversion of dark photons or axions to photons with wavelengths in the ~100 nm -- 20 micron range, improving reach beyond current constraints by up to several orders of magnitude.