# What happens to the diffraction pattern of light as an aperture becomes infinitely small?

Will the point source according to Huygens principle start radiating backwards with nothing to cancel it out?

Will it be a complete sphere if light passes through an infinitely small aperture?

• – user4552 May 1 '18 at 19:48

The Interference pattern behind an aperture in the far field is given by the Fourier transform of the aperture function. In the case of a 1-dimensional aperture, if the width of it is $d$, then the diffraction pattern is given by the function $$g(x)=\frac{\sin(x d)}{x} ,$$ where $x$ is the point on the screen. So, as $d$ goes towards $0$, you could argue that the pattern is just becoming more and more constant, going outwards from the middle of the screen. Of course since you are letting less and less light through, you could argue that the intensity also tends towards $0$ everywhere.