Ridged mirrors are not yet commercialized, although certain achievements can be mentioned. The reflectivity of a ridged atomic mirror can be orders of magnitude better than that of a flat surface. The use of a ridged mirror as an atomic hologram has been demonstrated. In Shimizu's and Fujita's work, atom holography is achieved via electrodes implanted into SiN 4 film over an atomic mirror, or maybe as the atomic mirror itself.