- A device that generates an intense directional beam of
→ monochromatic and
→ coherent light by exciting atoms to a higher
energy level and causing them to radiate their energy in phase.
The high degree of collimation arises from the fact that excited atoms are
are situated in a cavity bounded by two parallel front and back mirrors.
A first photon stimulates
an atom which emits a second photon, and so on thanks to the mirrors.
The resulting photons are all identical. They have the same energy which gives them
the same color and a unique direction. The first
working laser, a pulsed ruby device, was developed by T. Maiman in 1959.
See also → gas laser,
→ stimulated emission; → maser.
- The light produced in this way.
See also: Acronym for light amplification by stimulated
emission of radiation,
on pattern of → maser.
