Collimated light

Collimated light is light whose rays are parallel, and therefore will spread minimally as it propagates. A perfectly collimated beam, with no divergence, would not disperse with distance. Such a beam cannot be created, due to diffraction. Light can be approximately collimated by a number of processes, for instance by means of a collimator. Perfectly collimated light is sometimes said to be focused at infinity. Thus, as the distance from a point source increases, the spherical wavefronts become flatter and closer to plane waves, which are perfectly collimated.

Collimated light

Collimated light is light whose rays are parallel, and therefore will spread minimally as it propagates. A perfectly collimated beam, with no divergence, would not disperse with distance. Such a beam cannot be created, due to diffraction. Light can be approximately collimated by a number of processes, for instance by means of a collimator. Perfectly collimated light is sometimes said to be focused at infinity. Thus, as the distance from a point source increases, the spherical wavefronts become flatter and closer to plane waves, which are perfectly collimated.