effect of quantum reflection can be enhanced using ridged mirrors . If one produces a surface consisting of a set of narrow ridges then the resulting non-uniformity of the material allows the reduction of the effective van der Waals constant; this extends the working ranges of the grazing angle. For this reduction to be valid, we must have small distances, between the ridges. Where becomes large, the non-uniformity is such that the ridged mirror must be interpreted in terms of multiple Fresnel diffraction or the Zeno effect; these interpretations give similar estimates for the reflectivity . See ridged mirror for the details. Similar enhancement of quantum reflection takes place where one has particles incident on an array of pillars . This was observed with very slow atoms (Bose–Einstein condensate) at almost normal incidence. Application of quantum reflection Quantum reflection makes the idea of solid-state atomic mirrors and atomic-beam imaging systems (atomic nanoscope) possible. The use of quantum reflection in the production of atomic traps has also been suggested. Up to year 2007, no commercial application of quantum reflection was reported. References See also Atom optics Ridged mirror Casimir force van der Waals potential Quantum optics