It's well known that a human hair can diffract light (plenty of demos out there, all you need is a laser pointer and a strand of hair). I've been thinking, however: how can one model this process? The resulting diffraction pattern is pretty similar to that of a single slit (logical, since it's a single hair). However, the hair is blocking light, not letting it through like a screen would. I think it's reasonable to assume therefore an intensity profile at $z=0$ opposite to that of a single slit, assuming the strand has a diameter $d$:
$$I(x)=0 \ \ -d/2<x<d/2 \ ; \ I_0 \ \mathrm{elsewhere}.$$
It's "opposite" since a slit would have $I=1$ within the slit, and $0$ elsewhere. In this notation, I'm ignoring the vertical axis, but it can be accounted for assuming that the hair has length $L$. Do you think this is reasonable? Calculating the Fraunhofer diffraction integral seems to yield a cosine squared distribution.
