# Reduced absorption coefficient question

I came across a paper that reads

It is noteworthy that for a sample without lateral light propagation in the material, i.e. [reduced scattering] $$\mu_s' = \infty$$ and [absorption] $$\mu_a=0$$, ...

If there is no lateral light propagation from a collimated beam irradiating the surface of a turbid media, then this will mean that there is no scattering. Therefore, is the statement incorrect or what is the author indicating?

Reference:

• Maybe this is about the non-collimated case? Like sunlight in snow? Then there is no lateral transport of energy. – Pieter Feb 10 at 10:53