Despite our sci-fi dreams, laser cannons are still too bulky and inefficient to every be used on the regular by the military. But we may be getting closer to that laser-filled future.
MIT's Lincoln Lab spun TeraDiode off as a standalone laser-based company, and it's received a bunch of money from both DARPA and some venture capitalists. They're looking to commercialize a direct-diode laser, one that's supposedly brighter, more powerful and more focused than what's come before. It uses "a sophisticated optical system to manipulate individual beams to form a single output beam — a technique known as wavelength beam combining."
That all sounds well and good to me. Just call me when you fit it into a laser gun, cool?