Figure 3.

A graph showing the change of $f_i$ with incident angle as set out in Equation (3). All rays excluding ray 5 and ray 6 are shown here due to suppression from the capillary geometry considered. Parameters used were $r/R = 0.74$, $n_1 = 1.457$, $n_2 = 1.333$. The cut off for rays 3, 4, and 7 at ${\varphi }_i\sim 70°$ is due to these rays being unable to enter the core above this angle.