Question

What are coherent and incoherent sources?

Answer 1

Hint:In order to answer this question, we will go through the whole concept of both the coherent and incoherent sources separately. And then we will also give examples of both the sources. And we will also discuss which kind of light, both coherent and incoherent, is.

Complete answer:
We all know that light is a necessary aspect of life and that it may be classed by wavelength, intensity, uses, sources, colour, and frequencies. Photons make up light waves, which have different characteristics such as phase, amplitude, frequency, and period. Depending on the wavelength and frequency, the light produced by diverse sources has a variety of colours.
They are categorised based on the source of light they emit:

Coherent sources: A coherent source is one that generates light waves with the same frequency, wavelength, and phase or with a constant phase difference. When the waves superimpose and the maxima and minima positions are fixed, a coherent source produces long-term interference patterns. Prisms, lenses, and mirrors with particular parameters are used to create the coherent source.

Fresnel's biprism, Young's double-slit experiment, and Lloyd's mirror arrangement are some of the strategies that aid in the creation of coherent sources. The division of the wavefront is used in these techniques to create a coherent source.A coherent source is a type of laser. To generate extremely coherent light, LASER employs a phenomenon known as stimulated emission.

Incoherent sources: In order to create incoherent sources, conventional light sources are used. A light wave with a varied frequency, wavelength, and phase is emitted by an incoherent source. Transitions between energy levels in an atom are completely random in these waves. As a result, no control over an atom that would lose energy in the form of radiation can be formed.

Note: Laser light is both coherent and monochromatic (of only one 'colour'). When a source is incoherent, it emits light with frequent and unpredictable phase shifts between photons. (Incoherent light is produced by tungsten filament lamps and 'regular' fluorescent tubes.)