Can we say that a point light source (turned off) together with a two slit interferometer and say a photographic plate detector exclude certain photon modes? Light does not go to certain parts of the photographic plate so can we say that the source (turned off), the interferometer, and the detector together modify the electromagnetic vacuum so that when the point light source is turned on photons don't arrive at some regions because those modes of light can not be produced by the light source? Of course QED rules the land but does QED allow me to think as above? * (In a thread it was pointed out that one does not have to think in the force in the Casimir effect as due to vacuum modes being excluded but in this thread lets assume so.) I may be way out of line with my thinking, if so please help me get back in line. Thanks for any help!