Where does Photosynthesis sit wrt the total energy available?
There are too many unknowns involved. Photosynthesis is probably the cheapest way to recapture carbon as an energy source. I'd rather see the government fund such basic science than subsidize current types of renewable energy that can't compete with natural gas.
The beams generated by the device could, for instance, help materials scientists to make better solar materials by tracking the paths of electrons through solar cells, and might allow chemists to trace the ultrafast dynamics of photosynthesis and catalysis.