Ignore: How the interference pattern will look like in a double-slit experiment done with two different mediums? Air before the slit and glass after the slit.pic

Edit: How the waves pattern will look like in a double-One-slit experiment done with two different mediums? diffraction in the Air and refraction in the glass.

If light refract because one part of it is slower than the other then what will happen if the middle of the is wave slower the the others. pic reference