Before a detailed explanation of coherence, we must take a look at the laser beam. “Light amplification by stimulated emission of radiation” (laser) is a collective term from physics. The term laser denotes both the physical effect, such as the light beam and the corresponding 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. This is dependant on the type of laser
Lasers are found in a range of applications in everyday life. From laser pointers frequently used in presentations to tools for reading optical storage media such as Blu-rays or CDs, the laser beam has become indispensable in modern life.