A device which produces an intense, coherent, directional beam of light by stimulating electronic or molecular transitions to lower energy levels.
An acronym for Light Amplification by Stimulated Emission of Radiation.
A laser (Light Amplification by Stimulated Emission of Radiation) is a device which uses a quantum mechanical effect, stimulated emission, to generate a coherent beam of light from a lasing medium of controlled purity, size, and shape.
The output of a laser may be a continuous, constant-amplitude output (known as CW or continuous wave), or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching.
In pulsed operation, much higher peak powers can be achieved.