Why does light diffract?

Question

I know the wavefront theory but wavefront is imaginary. I want to know what exactly happens to light as it passes through a corner.

Answer 1

you should read Richard Feynman's QED. He explains all this better than I ever could.

Answer 2

The EM wave has both a E field and M field oscillating orthogonally, with a progation direction paralled to the poynting vector. When it hits a dielectric boundary, the maxwell's equtions has to satisfy the boundary conditions. they require the E component and M component to satsfy the Fresnel's relation, leading to the snells law, which govern how the different components of the two field behave as they passes through the boundary, imaginary wave decays transcendentally at surface as evanescence waves.

You might also ask why doesnt it go diffract with metal, well the oscillating field generates an electric current inside the metal o the field decays exponentially at the surface and boundary conditions implies reflection in this case;.

Answer 3

im guessing diffract as in bend? i forget the meaning of diffract well if that is the meaning then it diffracts because when light enters a substance that slows it down the slowing causes light to bend a little bit