Light of a uniform wavelength and stage; as used in lasers
Light in which the stages of most electromagnetic waves at each and every point-on a line normal into direction of this the beam are identical. Coherent light is normally monochromatic, in addition to most common way to obtain such light for practical utilizes is from a laser.
Light of a uniform wavelength and period; as found in lasers
Light where the phases of all electromagnetic waves at each point on a line regular to the way associated with the the ray tend to be identical. Coherent light is normally monochromatic, and the typical supply of such light for useful uses is from a laser.