A photonically controlled microwave device having a photosensitive substrate having an interior region comprising a high radio frequency (“RF”) field for a resonant RF mode. An RF resonator is patterned on a surface of the substrate, the pattern includes an aperture in the resonator positioned to direct light received from a light source to the interior region. The light source may have a wavelength that enables illumination of the interior region to generate free carriers or other photo-induced changes in RF permittivity. An optical boundary may be provided that recirculates the unabsorbed optical power inside the high RF field region until it is fully absorbed.