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azatkgz
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Please,can someone explain me spatial coherence?
Andy Resnick said:Spatial coherence is related to the size of a source, and means how well you can predict the field values *over there*, if I know what it is *here*. A point source produces a perfectly spatially coherent wavefront, while an infitely large source is perfectly spatially incoherent.
The van-Cittert-Zernike theorem is a very profound statement and worth spending time to understand. Briefly, the far-field diffraction pattern of a beam is proportional to the spatial coherence.
Spatial coherence is typically measured by a Younng's double-slit interfereometer, where the slit spacing is a measure of the spatial coherence.
Spatial coherence is the reason the holograms on credit cards look good outside in the sun, and terrible inside under fluorescent lights.
Spatial coherence refers to the degree to which different parts of a wave or signal are in phase with each other. In simpler terms, it describes how well the different parts of a wave or signal are aligned with each other.
Spatial coherence is important because it is a key factor in determining the quality of imaging and sensing systems. It also affects the behavior of light and other electromagnetic waves, making it crucial in fields such as optics and telecommunications.
Spatial coherence is typically measured using interference patterns, which are created when two or more coherent waves interact with each other. These patterns can be analyzed to determine the level of coherence between the waves.
The main factors that affect spatial coherence are the distance between the sources of the wave or signal, the wavelength of the wave, and any disturbances or obstructions in the path of the wave.
Spatial coherence has many practical applications, such as in holography, imaging techniques like optical coherence tomography, and in the design of high-speed communication systems. It is also important in fields such as astronomy, where it helps in the analysis of astronomical images and signals.