Changing the output frequency of a giant high energy chemical laser is extremely tricky. Frequency doubling demands a very pure coherence to get good efficiency, and even then "good" in this context means above 50% power converted to the new frequency. With a weapons laser, you're going to have a hell of a cooling problem in the converting medium. Then again, if reflective anti-laser coatings become common, it shouldn't be too difficult to add on a free electron laser system to burn off the mirror layer before the main beam strikes. A free electron laser can change operating frequencies trivially, just by adjusting its internal magnetic field.
It's a chemical laser but in solid, not gaseous, form. Put simply, in deference to you, Kent, it's like lasing a stick of dynamite. As soon as we apply a field, we couple to a state, it is radiatively coupled to the ground state. I figure we can extract at least ten to the twenty-first photons per cubic centimeter which will give one kilojoule per cubic centimeter at 600 nanometers, or, one megajoule per liter.
If I'd known computer science was going to be like this, I'd never have given up being a rock 'n' roll star. -- G. Hirst