Figure 6.
Schematic illustrating multiple scattering within the filter material. 1 – is an unobstructed reflected pathway that is included in the reflectivity (ρ) term along with all surface reflections. 2 – is an unobstructed transmitted pathway that is included in the transmissivity (τ) term. 3 – represents internally reflected energy off the inner interfaces, which are represented by calculated higher-order terms, but are generally small relative to the first order term (Equation (S6)). 4 – represents direct incident light (II) absorbed by a particle (p)/fiber (s), which is either absorbed or scattered, and its effect is included in the terms αi and σi, respectively, where i = ps, p, s. 5 – represents energy scattered from particles/fibers (a) that interact with other particles/fibers (b) and is included in the terms αi and σi.