did a quick searcg of this, and couldnt find anything, so hope its not been posted b4
but the US Airforce has developed a non lethal weapon system, inflicint pain upon the victims from up to 500m away. It works by firing a 94GHz millimeter wave which causes the air around the target to react, giving the victim an intolerable burning sensation
Bizare i know, but this is it in action
but the US Airforce has developed a non lethal weapon system, inflicint pain upon the victims from up to 500m away. It works by firing a 94GHz millimeter wave which causes the air around the target to react, giving the victim an intolerable burning sensation
Bizare i know, but this is it in action

They are waves though, all you need to stop it are a very fine mesh of metal, that is just slightly smaller than the wavelength, thus stopping the waves getting in! And light would probably still be able to pass through, like you can see through the mesh in the microwave 
