key term - Coherent Source

Definition

A coherent source refers to a source that emits waves with a constant phase relationship. In other words, the crests and troughs of the waves are aligned and maintain their positions over time.

Related terms

Interference:

The phenomenon that occurs when two or more waves overlap and combine either constructively (amplitude increases) or destructively (amplitude decreases).

Diffraction Grating:

A device consisting of many closely spaced slits or grooves that can separate incoming light into its component wavelengths.

Huygens' Principle: A principle stating that every point on a wavefront acts as a source of secondary spherical wavelets that spread out in all directions.