| Autor: |
Hartemann, F. V., Baldis, H. A., Luhmann, Jr., N. G., Le Sage, Gregory P. |
| Předmět: |
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| Zdroj: |
Encyclopedia of Electrical & Electronics Engineering; 1999 1st Edition, Vol. 3, p540-551, 12p |
| Abstrakt: |
The article discusses the concept of coherence, which, when applied to wave phenomena, implies a well-defined relationship in phase and frequency for the propagation of a wave or group of waves. Coherence distinguishes such phenomena from random noise signals, regardless of intensity or power level. In the case of electromagnetic waves, comparing a laser beam with an incoherent light source such as a flashlight qualitatively illustrates the fundamental features of coherence, as revealed by basic experiments. In particular, a laser beam readily produces interference patterns, thus exhibiting spatial coherence, and the intense, monochromatic character of laser light is an indication of its temporal coherence. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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