Incoherent and Coherent Light Sources

Light sources can be broadly classified into two categories based on the coherence of the emitted light:

• Coherent Source of Light
• Incoherent Source of Light

Let us understand what are they and how they are different from each other

Coherent Light Sources

Coherent Light sources exhibit a fixed phase relationship between the emitted waves. The waves maintain a consistent alignment of peaks and troughs, resulting in constructive interference patterns. Examples of Coherent Source of Light are:

• Lasers: Laser light is highly coherent, with a single wavelength and a well-defined phase relationship. This coherence is crucial for applications like holography and precision measurements.
• Certain Light-Emitting Diodes (LEDs): Some specialized LEDs, designed for coherence, exhibit properties similar to laser light, making them suitable for specific applications.

Incoherent Light Sources

Incoherent Light sources lack a fixed phase relationship between emitted waves. The phases are random and uncorrelated, leading to a broader spectrum of light. Key characteristics of incoherent sources include:

• Incandescent Bulbs
• Sunlight
• Fluorescent Lights

Difference Between Incoherent and Coherent Sources

Below is the difference between the Incoherent and Coherent Sources:

Incoherent Source is a light source in which the waves emitted from different points on the source are not correlated in terms of phase. In other words, the phases of the individual waves are not synchronized, and there is no fixed relationship between them. This lack of coherence means that the electromagnetic waves emitted from different parts of the source do not maintain a consistent phase relationship over time.

This article explores the fundamentals of incoherent sources, their definition, examples, and applications.