ExtremeTech pointed me in the direction of this one. Yes, lasers. These guys definitely have the military's attention. Why, you ask? What's so different about these gamma-ray lasers?

"'The difference in the power available from a gamma-ray laser compared to a normal laser is the same as the difference between a nuclear explosion and a chemical explosion,' said Dr David Cassidy of the University of California, Riverside, and one of the authors of the paper. 'It would have an incredibly high power density.'"