That means the beam produced is of higher quality than other lasers, is extremely straight (even by the exacting standards of a normal laser beam) and can thus be focused onto a small area.

ECONOMIST: Solar power from space

In this, the stream of video and audio data is recorded as a series of minuscule spots on the disc's surface that have been gently fried by a laser beam and turned from their normal crystalline condition to an amorphous state that has different reflective properties.

ECONOMIST: Digital video discs

From a standing start, the reconstructed beam sped back up to the normal speed of light.

BBC: NEWS | Science/Nature | Cool clouds turn light to matter