Figure 23.

Whispering-gallery modes (WGMs) in a dielectric microdisk. The refractive index of GaAs is $n=3.3$, and the polarization is TM. The different numbers are (for more details (see [61])): (a) $l=1$ and $m=19$; (b) $l=3$ and $m=12$, reprinted figure with permission from [61], Copyright (2015) by the American Physical Society.