# What does actually create the interference fringe on the screen: photon or classical wave?

I was reading G.I.Taylor's Single - Photon Double Slit experiment.

Now, at a time only a single photon gets emitted. What is the probability of it at a certain point of the screen to hit?

The answer is written rather abruptly:

Although the photon can hit anywhere, the probability is more, where the brightness(bright fringes) i.e. Intensity is more.

Now, this means intensity existed before photon actually hit the wall? How can it be possible?

When photon hits the screen, the energy gets transferred to the screen. So, after photon collides, intensity does come in discussion.

But if we accept the answer, it is like saying that energy came somehow on the screen before the photon; after that photons would strike there where the intensity of the energy is more. So, who is actually transferring the energy: photon or the waves? If it is wave that transfers energy as being evident from the above quoted argument, then what photons are doing actually ?? What are they meant for if they are not responsible for transferring energy??

• The photons (non-trivially) constitute the classical wave - these are not seperate entities, so I don't understand the question. – ACuriousMind Feb 1 '15 at 13:13
• The author of that quote is simply saying that the most probable regions for a single photon to hit turns out to be proportional to the intensity of the fringe patterns that you would expect classically. (And therefore the classical result can be explained in terms of individual photons interfering with themselves) – lemon Feb 1 '15 at 13:19
• @lemon: Then sir, photons actually interact with the screen,right? – user36790 Feb 1 '15 at 13:27
• They must interact with the screen to produce an image, yes... – lemon Feb 1 '15 at 13:48