These videos are part of Section 2 of the on-line course “Eagle Eye Astronomy”, initially released on France Université Numérique. These have recently been re-uploaded on youtube and close-captioned, to help better understand the audio track despite the French accent.
Turn the constraint of diffraction into an advantage: the interferometric trick
Understanding interference fringes: an electromagnetic theory of light
Stars are not lasers: a better model for ordinary light sources
Self-coherence and spatial incoherence of astronomical sources