We have reviewed different types of periodic structures (superlattices) induced by optical, infrared, and neutron irradiation. Both optical and electrical properties of these superlattices are analyzed, starting from the standard photorefractive model. New results on the thermoelectric and pyroelectric dynamic gratings are discussed in connection to the energy conversion and vibration sensing. For the neutron irradiation both real-time and static grating are analyzed, suggesting transmutation doping as a mechanism of recording.