A wavelength-converting optical structure is disclosed comprising a glass substrate, optical film, coating, or multilayer optical material incorporating one or more wavelength-converting materials configured to absorb ambient illumination within one or more spectral regions and convert and re-emit such illumination at different wavelengths. The converted emissions may pass through one or more surfaces of the structure into a surrounding environment to modify ambient illumination and provide at least one of antimicrobial illumination or photobiomodulation illumination. In various embodiments, the wavelength-converting materials may be incorporated within, coated on, laminated within, or doped into glass, films, coatings, or transparent substrates. The structures may be implemented in architectural glazing, transportation windows, consumer electronic displays, chemically strengthened cover glass, protective transparent surfaces, and other light-transmitting materials to enable passive environmental spectral modification without requiring an external power source.