Semiconductor photonic molecules

We have fabricated semiconductor photonic molecules based on microcavities with three-dimensional optical confinement. By connecting two or more microcavities by a semiconductor bridge structure, interaction between the optical modes of the individual microcavities can be observed. In the optical spectra the interaction leads to a splitting of the photonic ground state into an energetically favored and an energetically unfavored branch in analogy to the ground state of simple chemical molecules. By increasing the number of connected cavities, additional optical modes develop in the energy range of the fundamental and higher order modes of the individual structures. For systems with more than 10 connected microcavities, we observe a transition to a one-dimensional photonic crystal-like behavior.