الفهرس | Only 14 pages are availabe for public view |
Abstract There can be no doubt that the laser represents one *ojj-: the most remarkable scientific and technical. milestones of the 20th century. The dramatic growth of the laser technology began in 1960, when the first successful laser was reported. Lasers are now used in the most diverse fields: biology and medicine, cybernetics and computer circuitry, communications and radar systems, industrial processes, and measurements of various types. A Laser communication is one of the most distinguished comfnounication means due to its extreme directionality awl high information capacity as well as , high power concentration on the beam. As we know, the amount of information sent by electromagnetic signal is proportional to the signal bandwidth, and the spectral bandwidth of the laser beam is relatively large compared to microwave transmissions. Rangefinding is one of the most crucial applications in both civilian and military fields. It,-, Importance stems from the high spatial and temporal coherence of laser radiation. It is so coherent that it seems impossible to- use conventioii-al countermeasures against it. For instance, during air combat, it is very difficult to estimate the target range by the classical means in a very short time, due to high aircraft speed. |