Question

Define coherent sources of light.

Answer 1

Coherent sources of light:

1. Coherent light sources are those that emit a light wave with the same frequency, wavelength, and phase, or have a constant phase difference.
2. When waves superimpose and the positions of maxima and minima are fixed, a coherent source produces sustained interference patterns.
3. Sound waves are produced by speakers that are powered by electrical signals of the same frequency and phase.
4. A laser is another example of a coherent source.
5. Lasers are commonly used as coherent sources because they generate highly coherent light via a phenomenon known as stimulated emission.
6. Small light sources are at least partially coherent. This explains why we can see interference patterns on soap bubbles and enjoy the iridescence of butterfly wings.
7. While sunlight is incoherent, small areas of sunlight are generally partially coherent.