Universal parameter to describe the reduction of refraction effects in the scattering of absorbing spheres

The scattered intensity from large spheres with a real part of the refractive index of n=1.33,1.5,2.0 is investigated as the radius R and an imaginary part of the refractive index κ are varied. It is shown that the product of κ and the size parameter kR, κkR, is a universal parameter describing the quenching of the refraction phenomenon of the scattered light: the refraction hump, the generalized rainbows, and the glory. The physical reason for this is that κkR is the inverse of the relative skin depth of light penetration into the sphere, which is demonstrated by calculations of the internal fields that darken universally as κkR increases.