Thick Pinhole and Spot size

Didn't seem to have much luck on the actual reasoning with this elsewhere.

A regular pinhole projects an image, and has a diffraction limit for the image, that is the size of the airy disk.

What if we take a thick pinhole, no a pinhole in metal foil for example, but a long solid cylinder, several cm (or longer if need be) thick, with a fine pinhole drilled through it.

Can this project a non-image very fine spot that is smaller than the diffraction limit of a thin pinhole of the same diameter?

Oblique rays are essentially cut out, and you're left with on-axis.


I know someone will bring up ripple simulations / diffraction waves, like water down a long hallway (or sewer), it'll bounce off the walls, interfere with itself and propagate forward, and spread out at the exit.



But there are some obvious differences that are usually more or less neglible in thin aperture ripple simulations.

What if the material absorbed the wave as it hits the material of the aperture. This only portion of the wave to make it out, would be the center portion propagating on a narrow enough angle to avoid hitting the material.


Any idea on this?