Talk-Polywell.org

Via Physorg:
http://www.physorg.com/news/2011-05-gam ... clear.html

In the new study, Eugene Tkalya from the Institute of Nuclear Physics at Moscow State University has theoretically proven how the stimulated gamma emission of thorium nuclei can emit coherent visible light. Although the nuclear gamma-ray laser emits light based on stimulated emission, it operates a bit differently than a normal laser.

Still only a theoretical model, but the paper is pretty nice and worth a read if you have some free time:
http://arxiv.org/PS_cache/arxiv/pdf/101 ... 0858v3.pdf

I guess thats one step closer to someone building a working GRASER.

well, no, not Gamma-ray. 162 nm UV; Thorium 229 has a nuclear excited state at just 7 kev. There are a few other atoms with a first excited state this low, too.

The trick is exciting a nuclei with that LITTLE energy. In this case, you can use a more random photon source.

Yeah, now that I double check the numbers, there is a bit of a difference between 162nm and 10^-11m wavelength where the gamma range starts.

It seems to me, though, that is you can find nuclei with excited states below their neutron or proton separation energy that you can turn a rather random energy source into a laser of the appropriate wavelength. Of course the absorption of photons by nuclei is a lot less common than that of absorption by electrons around the atoms, so your efficiency will be extremely low, unless your energy source is something screwy like low energy excited neutral particles. Say, 100 keV pi-0 mesons or something.