Subject: Does dual slit interference cause distribution of probability or E/M wave?

In a dual-slit photon interference experiment allowing a single photon to emit, 
would it impact with twice the energy in one region and zero in others?  Is it 
a superposition of probability, or electromagnetics?  In the standard wave 
particle duality (packet of energy vs. EM wave) -- I thought it was the EM wave 
that interferes... but since the laser's color is unchanged, isn't it actually 
the probability of path that interferes?  Then where does E/M come in?

Re: Does dual slit interference cause distribution of probability or E/M wave?