How long before directed energy weapons make there way onto the modern battle fields?

I'm just curious because i read in popular science that the army is working on microwave cannons and electromagnetic rail-guns.How long before directed energy weapons make there way onto the modern battle fields?
it already is... here is one you can check out



http://www.popularmechanics.com/technolo鈥?/a>



edit:

here is another one for ya

http://www.telegraph.co.uk/news/newstopi鈥?/a>How long before directed energy weapons make there way onto the modern battle fields?
they are already in use, but are too expensive for use in combat, so until they find a cheap way to mass produce them, they wont have them.How long before directed energy weapons make there way onto the modern battle fields?
I doubt a radiation-type weapon is going to be more cost-effective than a chemical-propelled projectile weapon any time this century. To match regular guns, you'd need batteries or capacitors with an energy density as high as that of gunpowder, and I just can't see that happening.



The railguns are interesting, however. I think they will be made cost-effective in this century.