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Can Some one Explain What is Speckle pattern and Where speckle Occurs?

Can Some one Explain What is Speckle pattern and Where speckle Occurs?

Grade:12

1 Answers

ravi pratap
12 Points
14 years ago

A speckle pattern is a random intensity pattern produced by the mutual interference of a set of wavefronts. This phenomenon has been investigated by scientists since the time of Newton, but speckles have come into prominence since the invention of the laser and have now found a variety of applications.




A familiar example is the random pattern created when a laser beam is scattered off a rough surface - see picture. A less familiar example of speckle is the highly magnified image of a star through imperfect optics or through the atmosphere (see speckle imaging). A speckle pattern can also be seen when sunlight is scattered by a fingernail.

The speckle effect is observed when radio waves are scattered from rough surfaces such as ground or sea, and can also be found in ultrasonic imaging. In the output of a multimode optical fiber, a speckle pattern results from a superposition of mode field patterns. If the relative modal group velocities change with time, the speckle pattern will also change with time. If differential mode attenuation occurs, modal noise results.

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