What is the term for wavelengths that are synchronized in time and space?

The term for wavelengths that are synchronized in time and space is known as coherent light. Coherent light refers to light waves that have a constant phase relationship – meaning that the crests and troughs of the waves coincide – and they propagate in unison. This characteristic is crucial in many optical applications, including lasers, where coherent light is essential for producing clear, focused beams that can travel long distances without significant spreading.

In contrast, monochromatic light consists of a single wavelength or color of light but does not necessarily imply that the waves are coherent. Divergent light, on the other hand, refers to light that spreads out as it travels, generally not maintaining synchronization, while incoherent light consists of waves that do not have a fixed phase relationship, leading to a random distribution of phases and wavelengths. The unique quality of coherent light makes it particularly valuable in various technologies, such as interferometry and holography.