Intense ray of light (5,4)
I believe the answer is:
laser beam
'intense ray of light' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for laser beam that I've seen before include "Column of intensified light" , "Intense ray of light" , "Shaft of light or electromagnetic radiation" , "penetrating light" , "Shaft of light or electro-mechanic radiation" .)