Angle of the transmitted wave, θ_T (Eq. (27)), as a function of the incidence angle, θ_I, for different values of the density contrast, ρ_c. The intersections of the curves with the horizontal axis correspond to the Critical angle, θ_C, whereas the diamonds denote the Brewster angle, θ_B, for the different density contrasts. The red dotted line shows that θ_T + θ_B = 90°. In this figure one can see that also in the case of ρ₀₂ > ρ₀₁ the sum of the Brewster angle and the transmitted angle is equal to 90°.