Hybrid modes of open waveguide cavities (numerical and analytical investigation)

Conclusions

We see that the behavior of the spectral curves near regions of mode interaction can be reconstructed by determining the set of Morse critical points and the expansion (3). If these curves are augmented with corresponding asymptotes of the form Re ϰ(L) → ν _n /2πθL≫1, Im ϰ(L) → 0 fairly detailed information can be obtained about the behavior of the eigenfrequencies of the investigated structure. This approach is most effective in cases where mode interaction can be expected beforehand on the basis of general considerations when the sequence of excitation of the OWC and the energy-converting properties of its boundaries are known. By solving Eq. (4), we can predict unambiguously whether such interaction will take place and, if so, for what geometrical and frequency parameters. Once the coordinates of the Morse point are known, the structure of the field can also be effectively and deliberately varied without any appreciable change in the OWC geometry.