In atomic physics, a ridged mirror (or ridged atomic mirror, or Fresnel diffraction mirror) is a kind of atomic mirror, designed for the specular reflection of neutral particles (atoms) coming at the grazing incidence angle, characterised in the following: in order to reduce the mean attraction of particles to the surface and increase the reflectivity, this surface has narrow ridges.
Reflectivity of ridged atomic mirrors
Various estimates for the efficiency of quantum reflection of waves from ridged mirror were discussed in the literature. All the estimates explicitly use the de Broglie theory about wave properties of reflected atoms.
Scaling of the van der Waals force
The ridges enhance the quantum reflection from the surface, reducing the effective constant of the van der Waals attraction of atoms to the surface. Such interpretation leads to the estimate of the reflectivity
where is width of the ridges, is distance between ridges, is grazing angle, and is wavenumber and is coefficient of reflection of atoms with wavenumber from a flat surface at the normal incidence. Such estimate predicts the enhancement of the reflectivity at the increase of period ; this estimate is valid at . See quantum reflection for the approximation (fit) of the function .
Down six points, the Titans found themselves in a similar spot as Friday’s fourth-round matchup against MarvinRidge... The shots weren’t falling, allowing Marvin Ridge to snag a late first-half lead.
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is distance between ridges, 
is 
is wavenumber and 
is coefficient of reflection of atoms with wavenumber 
from a flat surface at the normal incidence. Such estimate predicts the enhancement of the reflectivity at the increase of period 
. See 
.