Solid line: total specific intensity of ordinary photons obtained from the sum of the first ten terms of the Fourier series of Eq. (31). Dot-dashed line: specific intensity of ordinary photons for the first Comptonization model k = 1 (Eq. (40)). Dashed line: specific intensity of extraordinary photons created via mode-switching from a fraction of ordinary photons as calculated in Eq. (34). The optical depth of the slab is τ₀ = 20; the seed photon spectrum is a black-body with kT_bb = 1 keV; while the electron temperature is kT_e = 10 keV. The case of photons escaping with an angle μ = 0.5 with respect to the slab normal is shown.