MERGING LASER BEAMS INTO ONE BEAM (WHERE HAVE I HEARD THAT BEFORE?)

April 12, 2017 By Joseph P. Farrell

I received the following article this week from Mr. J.K., and when I read it, I had to smile... very nervously, for it seems that scientists have figured out how to combine several laser beams into one beam, to increase the power of the emergent beam, and also to reduce the heat generated from just one large, rather than several small, beams. That, of course, is the premise of George Lucas' rather fanciful one-shot planet-destroying weapon from his Star Wars movies, the Death Star. But, believe it or not, that's not what made me smile nervously, for obviously, humanity is nowhere near being able to construct an object that big to house and aim an equally gigantic laser, much less to move it through space.  What made me smile nervously was...

... well, read it for yourself:

It’s Now Possible To Combine Lasers Like In The Death Star

Just for kicks, we can add the following much more scientific article, before returning to the first:

Photonic Frontiers: beam combining - Combining beams can boost total power

Note, that in the second article, it is admitted that combining several beams into one can be a method of dealing with the problem of the tremendous heat that lasers generate, and also that it is a method for increasing power, with this very important caveat:

Combination of larger arrays of laser elements to produce good quality beams has been demonstrated only at lower powers. Other challenges include balancing the tradeoffs between diode arrays and arrays of fiber lasers, reducing the light lost to side lobes, and efficiently combining light from input arrays with relatively low fill factors.

The big questions are how high can the power go, and how well will it scale?

Our friends at phys.org are a little more "flashy" in their coverage of the phenomenon:

The Star Wars 'superlaser' may no longer be sci-fi

Diamond makes laser beams more brilliant

Basically, the new technique involves shooting several laser beams at a very pure diamond, which due to its lattice properties combines the incoming beams into one outgoing beam, and at the same time changing its frequency. The result is an increase of power in the beam, without the increase of heat that would be generated by one beam to begin with.  Then comes this admission from the first phys.org article cited above:

Although other materials have exhibited the same type of beam combining properties, the choice of diamond is essential for high power. The power-transfer effect at the heart of the device, called Raman scattering, is particularly strong in diamond. Also, crucially, diamond is outstanding for its ability to rapidly dissipate waste heat.
At this point, my calm smile, brought on by confident knowledge that we were nowhere close to being able to build gigantic moons with laser beam-combining to blow up planets(much less actually be able to move the thing), began to acquire a slight twinge of nervousness, for the final statement indicated that "they" were testing the whole technique on a variety of materials, doubtless to find the most optimal for power output and heat dissipation.
Which brings us back to the first article that Mr. J.K. sent me, where, sure enough, my worst suspicions were confirmed:

Planetary destruction is not on the cards for this technology, but it has applications for both defense purposes and scientific analysis. Laser technology is crucial in many areas and this will allow lasers to go beyond the current power limits.

“Researchers are developing high power lasers to combat threats to security from the increased proliferation of low-cost drones and missile technology,” Professor Mildren explained. “High power lasers are also needed in space applications including powering space vehicles and tackling the growing space junk problem that threatens satellites.” (Emphasis added)

And of course, what can be used to zap "space junk" into vapor can be used to zap satellites, or missiles, into vapor... and one day, perhaps, on a sufficiently large orbital platform, to be used in more horrific offensive strategic "mission configurations" against ground targets...

Smile. Remember, we're nowhere close. Remember, that when H.G. Wells started writing about atomic bombs in his science fiction at the turn of the last century, it took a whole 45 years to invent them. Have a nice day.

See you on the flip side...