Expert: Daniel Mazur - 11/28/2007

Question
Hi:

Is it physically-possible to design and build a 400 nm laser that is directly-"pumped" by aneutronic nuclear fusion and in which the active laser medium is a rare-earth crystal?

The "pump" is the part of the laser that excites the atoms in the laser medium.

Hydrogen-Boron fusion is an example of aneutronic fusion. 400 nm is the wavelength of "black light" and is about the shortest the human eye can detect.

In aneutronic fusion no more than 1% of the total energy released is carried by neutrons.


Thanks,

Green

Answer
Hello,
I cannot say it is impossible, but:
* the H+B fusion and all aneutronic fusion reactions are still very little known. Physical realization of a laser needs the "pump" source to be of reasonable physical dimensions, that will be the practical limiting factor.
* As long as we have a medium with the desired 3.1eV light-emitting transition, we need to make sure that it can be pumped by the source at hand - in this case gamma rays 8.7MeV. Maybe there is a rare-earth crystal matching these requirements, but even if there is, I am not sure of the usefulness. After all, 8.7MeV is a large energy and there may be some damage inflicted on the crystal by secondary effects of ionization. Somebody may have already done an experiment with irradiating rare-earth crystals and looking for any damage, I am not aware of such work, however.

Sorry I couldn't give you a more optimistic answer.
Best,
Daniel