The reciprocal space correlation function
r(
kx,
ky,
τ) for lag
τ = 0.451 s of a diffusing microsphere sample both (
A) before and (
B) after circularly averaging and taking the natural logarithm. The data was fit to Eq. 23, and the slope of the first segment is

. In this case, the first segment of the circularly averaged correlation function has a line of best fit of
r(|
k|
2, 0.451 s) = −0.0312
μm
2|
k|
2 − 0.930. The (
kx,
ky) = (0, 0) point, which corresponds to the DC component of the Fourier transforms, has been omitted in these figures, and is not used for fitting.