Dressing Intense Lasers for Increased Range
Lasers are a pretty cool piece of technology, in large part because of their variety of applications. They can help annotate a presentation, measure distances, read codes, to give a few examples, but one day they may also affect the weather. One barrier to using lasers to trigger rain and lightning has been that intense lasers will dissipate quickly in air, but researchers at the University of Central Florida have made a discovery that may help with that.
It may seem odd that rain and lightning could be controlled with lasers, but this is actually something that has been known about for years. Lasers of the proper power and frequency can excite electrons, creating a plasma, and both water condensation for rain and lightning are linked to static charged particles. If a laser is used to excite more charged particles, rain and/or lightning can be produced. The catch is that such intense laser beams will actually dissipate over short distances forming filaments. This is caused by the beam naturally wanting to collapse, but the excited air molecules wanting to spread it out. What the Florida researchers discovered is that if another, low-intensity beam is wrapped around the primary one, it will keep the primary beam from dispersing, increasing its range.
When tested the researchers were able to extend a laser pulse from just 10 inches long to 7 feet, but in theory this technique could extend it to over 50 meters. Along with potentially triggering rain and lightning, this research could be applied to guide microwave signals over very long plasma channels.
Source: University of Central Florida