If I had a perfect glass(completely transparent) pane, with a slit cut into the center, that has a length lesser than the wavelength of photon A, and I shoot a stream of photon A perpendicularly to the slit,(the whole apparatus in a vacuum), will the photons show the single slit diffraction phenomena on the other side, or would just it pass through the transparent glass?

Edited August 16, 201312 yr by Mellinia

I would expect a diffraction pattern to appear. Some light will pass through the slit, and will (in general) have a different phase than the light passing through the glass. The question is how much light will diffract.

 

Not too different from holographic transmission gratings, except you only have one slit in this example.

Yup, the question indeed is how much light will diffract.
Would most of the photon energy prefer to go through the slit instead of the glass, since the slit is a vacuum?

Yup, the question indeed is how much light will diffract.

Would most of the photon energy prefer to go through the slit instead of the glass, since the slit is a vacuum?

If the glass is thin (as you said) it may be as simple as the fraction of the light incident on the slit. I can't think of a reason for the light to preferentially travel in the glass or not enter the slit, unless it's thick enough to act as a waveguide. Then it seems similar to coupling into a hollow-core fiber, which would be a mode-matching issue.