Suppose we have two laser diodes that are made to transmit light at the same wavelength and intensity. Also, suppose that we place them in an open space and separate them by a distance such that when their generated beams intersect at one point in space and one point only. Further suppose that they add constructively at that point. Laser 1 = A sin wt Laser 2 = A sin wt Laser 1 + Laser 2 = 2 A sin wt However the sum of the energies of the two waves does not equal the energy of the sum of the total. Can someone clarify that? It's been bugging me for a while.