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easyrider
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I know that lasers will always have divergence due to diffraction. With that said, they don't diverge until after the point of focus, correct? Is there a limit to how far a laser can be focused?
Andy Resnick said:There has been some work on deep-space communication systems (NASA's LCRD and LADEE experiments), and AFAIK there's a multi-satellite design by ESA that uses lasers to remain in a fixed configuration for gravitational wave detection (LISA)- not sure what stage in development they are, tho.
Note that atmospheric turbulence/scattering makes long distance laser systems (Boeing's airborne laser system, for example) hugely complicated- the THEL (Nautilus) system was shelved.
Laser divergence refers to the degree to which a laser beam spreads out as it travels. This is an important consideration because a high divergence can significantly reduce the intensity and precision of the laser beam, limiting its usefulness for certain applications.
The divergence of a laser beam increases as it travels through space. This is due to a phenomenon known as diffraction, where the beam spreads out due to interference with the surrounding air molecules. The longer the distance traveled, the greater the divergence and the weaker the laser beam becomes.
While divergence cannot be completely eliminated, it can be controlled through various techniques. For example, using a beam expander can decrease divergence, while using a collimator can increase it. Additionally, choosing the appropriate laser wavelength and using high-quality optics can also help minimize divergence.
Laser divergence can have a significant impact on applications where precision and accuracy are crucial. This includes laser cutting, welding, and drilling, as well as laser-based measurements and scientific experiments.
Laser divergence can be calculated using mathematical equations that take into account factors such as the laser beam's wavelength, diameter, and distance traveled. To measure divergence, specialized instruments such as a beam profiler or a beam divergence meter can be used.