The government probably already has weapons much more advanced than this but are just keeping them secret, as usual.
This.
Just think. That new ion engine/thruster that is going on all future spacecraft? Built in 1959 by Harold R. Kaufman.
The A-12 Blackbird, with all its cool toys? First
flown in 1962.
Not to mention all the cool stuff on Futureweapons that gets shown.
Of course the military has military grade laser weaponry. Maybe even plasma weaponry. Who knows what they have?
Why aren't we using them? We don't need to... yet. It's cheaper to arm a soldier with an M4. If it ain't broke, don't fix it.