Hmm. How to explain this...
Yes.
They have gravity generators capable of producing fields in the range of millions of g, unidirectionally. They can make very large lasers. Obviously, as we can make very large lasers
now, and I can't believe that in a century-plus of advancement that wouldn't be something that was researched heavily. And there is basically no theoretical upper limit to how big you can make something like a carbon dioxide laser, the only limit is really an engineering one.
So you combine these two simple inventions. What happens if you fire a laser into a very intense gravity field? That's right, it causes blue shift. What's blue shift? Raising the wavelength and therefore increasing the frequency of the photons, by adding kinetic energy to them.
So, you put a massively powerful IR laser into one end of your gravitational accelerator and you get a massively powerful x-ray laser out the other end. Turn it up a little more and you get a gamma laser. Beam divergence decreases as wavelength decreases, so jacking up your laser from IR to gamma hugely reduces the spot size at any given range, which in turn even more hugely increases the energy density. The shorter wavelength allows more of that energy to be absorbed into the target. And so on.
You end up being able to slice bits off asteroids from a million kilometers away without any effort at all assuming you can actually hit the thing and pump enough energy into the beam. I ran the numbers in the BOLO thread at one point, and the maximum range is pretty amazing.
Of course, if you can run it continuously at that power level, you just raster scan the area you think the ship will be in
And you can't really dodge a laser. Especially as you can't see it except where it interacts with something, and if that something is you, it's way too late. There's also the minor issue that it's
a gamma laser so even a glancing hit is going to produce secondary radiation that will irradiate the hell out of anything in the way. That's the biggest issue with it, really. You might have to turn it down to extreme UV to be safe...
And you can steer it with a gravity field too, as well as focus it. Gravitational lensing is an interesting thing.
Yeah, they've got plenty of weapons options that don't need something as fiddly as planium