Coherent light is a beam of photons (almost like particles of light waves) that have the same frequency and are all at the same frequency. Only a beam of laser light will not spread and diffuse. In lasers, waves are identical and in phase, which produces a beam of coherent light.

What does coherent mean in light?

Coherence, a fixed relationship between the phase of waves in a beam of radiation of a single frequency. Two beams of light are coherent when the phase difference between their waves is constant; they are noncoherent if there is a random or changing phase relationship.

What is an example of coherent light?

An example of a coherent source of light is the laser light. The emitted light from the laser has the same phase and frequency. Another example of coherent sources is the sound waves. At the same frequency and phase, the electrical signals travel from the sound waves.