Shadow Edge in Vacuum: Intensity & Wavelength

[rjbeery]

Does a shadow in a vacuum possesses a distinct edge, or does the intensity at the edge taper over an area proportional to the wavelength of light being obstructed?

 

[mgb_phys]

You get a diffraction pattern - called knife edge diffraction

http://demonstrations.wolfram.com/FresnelDiffractionAtAnEdge/

 

[rjbeery]

Perfect. Thanks so much