In Young's double slit experiment, we usually shine a beam of light over two (or more) slits, as a result of which an interference pattern is observed on the screen. This is because as a beam passes through a slit, it acts as a secondary source of light, thus radiating light in all directions, much like what we do in Huygen's principle. The light from these two slits can interfere either constructively or destructively (or neither), which explains the alternating dark and light fringes.
My doubt is, if we reduce the intensity of the incident beam to that of a single photon, what would happen?
Would we observe just two maxima on the screen, directly in front of the two slits, or would there still be an interference pattern (based on some quantum principles maybe)?