DIFFRACTIVE OPTICS: MDOE produces variable optical power.

The article focuses on a study of combining a patterned defractive optical elements (DOE). It notes from a discovery of researchers, Stefan Bernet and Monika Ritsch-Marte on combining the patterned DOE to produce a moiré effect of variable focal length and have seen with a practical application. Furthermore, it explores on the approaches that the researchers used in developing optics that has variable optical power.