Range of these weapons is quite complicated, there is always a bit of divergence of the rays, scatter off particles, reflection off water vapour and absorption in gases. In the vacuum of space the only significant limit to range is the divergence.
In a time of universal deceit - telling the truth is a revolutionary act. George Orwell
When the debate is lost, slander becomes the tool of the loser. Socrates
There is another topic about this somewhere. The technology isn't complicated. They tried it for shooting down satelites (read ballistic missiles) but missed the satelite and released a metre wide beam of 8 seconds duration of massive energy into space which will carry on forever at the speed of light until it hits something (hopefully an asteriod and not something belonging to a race more intelligent than us!)