In
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which rel ...
, an atomic mirror is a device which
reflects neutral
atoms
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas ...
in the similar way as a conventional mirror reflects
visible light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
. Atomic mirrors can be made of
electric fields or
magnetic field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and t ...
s,
electromagnetic wave
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible ...
s
or just
silicon wafer; in the last case, atoms are reflected by the attracting tails of the van der Waals attraction (see
quantum reflection).
[
] Such reflection is efficient when the normal component of the wavenumber of the atoms is small or comparable to the effective depth of the attraction potential (roughly, the distance at which the potential becomes comparable to the kinetic energy of the atom). To reduce the normal component, most atomic mirrors are blazed at the
grazing incidence.
At grazing incidence, the efficiency of the
quantum reflection can be enhanced by a surface covered with ridges (
ridged mirror).
[
]