Jahn-Teller effect in photonic crystals

The Jahn-Teller effect in photonic crystals as a prototype of photon-phonon interactions is studied. We are interested in removing the degeneracy of a defect state due to coupling with vibronic mode. Two-dimensional square photonic lattice of the dielectric rods in vacuum doped by the defect rod, giving the doubly degenerate E state in the first TM band gap is studied. We show that coming from the Jahn-Teller theorem, the lattice vibration with the symmetry of B₁ and B₂ modes should result in splitting the degeneracy of the E photon state, the lattice vibration being frozen. The stable configuration in the presence of the Jahn-Teller effect is determined from the dependence of the energy as a function of the rod displacement. Using the value of the vibronic constants, obtained from the suppercell plane wave calculations and the Finite Difference Time Domain simulations, we find the stable configuration of the lattice. We discuss the conditions to observe the effect.