Finite-element modeling of coupled optical microdisk resonators for displacement sensing

We analyze normal mode splitting in a pair of vertically coupled microdisk resonators. A full vectorial finite-element model is used to find the eigenfrequencies of the symmetric and antisymmetric composite modes as a function of coupling distance. We find that the coupled microdisks can compete with the best Fabry–Perot resonators in displacement sensing. We also show how we configured FreeFem++ for the sphere eigenvalue problem.