Question

Which lens is used in Fresnel diffraction?

Answer 1

1. When the distance between the obstruction and the screen, or the distance between the screen and the obstruction, is comparable to the size of the obstacle, Fresnel diffraction occurs.
2. Fresnel diffraction utilizes a convex lens.
3. The Kirchhoff–Fresnel diffraction can be approximated in optics by using the Fresnel diffraction equation for near-field diffraction, which is applicable to the propagation of waves in the near field.