To explain coherence more specifically, we need to first take a look at the laser beam itself. The “light amplification by stimulated emission of radiation” is a collective term from physics. The term laser represents both the physical effect, i.e. the light beam itself, and the corresponding laser device (laser machine, laser source).
- Are electromagnetic waves
- Often have a very narrow frequency range (narrow-band emitter)
- Consist of a sharply focused light beam
- Have a long coherence length, depending on the type of laser
In everyday life, lasers are found and used in a wide variety of applications. It could be as simple as a laser pointer, which is often used in presentations and in power tools, or it could be for reading optical storage media such as Blu-rays or CDs: The laser beam has become indispensable in modern life.