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Coherence is a measure of how well a signal, such as a optical wavefront, correlates with itself. For example, if you measure a peak at one point in space and time, what is the chance that you will measure a peak at another space and time? This hints that there are actually two forms of coherence, one related to time and the other to space.
Temporal coherence looks at how well radiation measured at one single point correlates over time. In other words, if you measure a peak at one moment in time, how well can you predict that you'll measure a peak at another moment in time? Temporal coherence generally requires a small spread in wavelengths and a source which emits light in-phase. Lasers typically have high temporal coherence, while sunlight, which has a broad emission spectrum, has a low temporal coherence.
But that's not the end of the answer.
The other type of coherence is spatial coherence, and relates to how well two points on an emitter are correlated. One classic way of demonstrating spatial interference is the double-slit experiment: put two small slits in a sheet, and check to see that the light from the slits interferes constructively. Spatial coherence generally requires a small degree of angular spread. Again, most lasers have high spatial coherence. Sunlight also has high spatial coherence: because the sun is so far away, the rays of light are almost parallel.
The coherence of sunlight has been studied since 1869 (Agarwal et al, "Coherence properties of sunlight", Optics Letters 29, p. 459, 2004) -- but even with more than a century of coherence, the subtle difference between spatial and temporal coherence can be tricky.
What else can I help you with?
Is sun a coherent source?
Yes, the sun is a coherent source of light because its electromagnetic waves have a fixed phase relationship and travel in a consistent direction. This coherence allows for interference patterns to be observed in phenomena like diffraction and Young’s double-slit experiment.
What are light waves that moves together as they travel away from their source?
This phenomenon is called coherence, where light waves maintain a constant phase relationship as they propagate. This is important for applications like holography and optical coherence tomography.
Is it possible to have coherence between light sources emiting light of different wavelengths?
Yes, it is possible to have coherence between light sources emitting light of different wavelengths. Coherence refers to the phase relationship between two waves, and it is not dependent on the wavelengths of the light. However, achieving coherence between light sources of different wavelengths may require careful control and alignment of the sources.
Is a mirror a natural source of light?
A mirror is not a source of light, natural or otherwise.
Distinguish between a luminous source and an illuminated source?
A luminous source produces its own light, like the sun or a light bulb. An illuminated source does not produce light but reflects light from a luminous source, such as the moon reflecting sunlight.
Is sun a coherent source?
Yes, the sun is a coherent source of light because its electromagnetic waves have a fixed phase relationship and travel in a consistent direction. This coherence allows for interference patterns to be observed in phenomena like diffraction and Young’s double-slit experiment.
Is the sun a light source?
Yes, the sun is a light source because it shines light on earth.
Is sun a light source?
Yes, the sun is a light source because it shines light on earth.
Is the moon a natural source of light though it reflects the sun's light?
No- it reflects the natural light of the sun, so the sun is the source.
What is a light source?
The Sun is a light source Something that makes light.
Which planet is a source of light The earth the moon or the sun a satellite?
The sun is a source of light, but it is not a planet.
What is independent light source?
The sun is an independent light source.
What is light from a light source?
the sun
What is the source of the light used in photosynthesis?
sun light
What makes the sun a nuclear light source?
The sun is a nuclear light source because you can see light, right? The sun gives out light energy so you can see in the daylight.
What are light waves that moves together as they travel away from their source?
This phenomenon is called coherence, where light waves maintain a constant phase relationship as they propagate. This is important for applications like holography and optical coherence tomography.
What source of light keeps earth alive?
The Source of light is the sun
