Figure 2

Testing mode coupling/mixing hypotheses.

(a) and (b) show the intensity distribution and the change in its center axis intensity resulting from the simulated propagation of a plane wave through the ommatidium model in Methods. Both confirms the mid-CC focusing by CL near z = 58 μm. The inset in (b) shows the change in the overlap integral η between z = 55 and 68 μm. (c) The amplitude and phase profiles at the focal spot (z = 58 μm). They agree well with those of Airy pattern except for the peripheral, low-intensity part (ρ > 5 μm). (d) The amplitude and phase profiles obtained at the Rh entrance (z = 68 μm), however, exhibit significant mismatches from the Rh waveguide's LP₀₁ mode, indicating that the hypothesized mode coupling or mixing mechanism is insufficient for transforming an Airy-like pattern into LP₀₁.