Collimated light
Collimated light' is light whose rays are parallel, and therefore will spread slowly as it propagates. In theory,  collimated light does not disperse with distance. Really, collimated light will disperse a little as it travels over distance. Diffraction prevents scientists from creating a perfectly collimated beam with no divergence. Light can be approximately collimated by a number of processes, for instance by using a collimator. Some people say that collimated light is focused at infinity. So, as the distance from a point source of light increases, the spherical wavefronts become flatter and closer to plane waves, which are perfectly collimated.