Abstract:We investigate the energy splitting, quality factor and polarization of the fundamental modes of coupled L3 photonic crystal cavities. Four different geometries are evaluated theoretically, before experimentally investigating coupling in a direction at 30 • to the line of the cavities. In this geometry, a smooth variation of the energy splitting with the cavity separation is predicted and observed, together with significant differences between the polarizations of the bonding and anti-bonding states. The controlled splitting of the coupled states is potentially useful for applications that require simultaneous resonant enhancement of two transitions. This compares with V = 0.76(λ /n) 3 for an isolated cavity in the same lattice. 20. Three other modes exist between the + − 1 and − − 2 modes. Unfortunately, the close spacings and low quality factors of these other modes [18] make it impractical to identify their peaks unambiguosly in Fig. 3. It is, however, likely that the predicted 1.5 meV splitting of the + + 1 mode is responsible for the most prominent features; the predicted splittings of the other two modes are insufficient to explain the peak around 1.32 eV. 21. Note that the results for the FDTD simluations become inaccurate for the largest cavity separation, since the intensity above the center of the double cavity becomes very low. 22. E. Gallardo, L. J. Martínez, A. K. Nowak, H. P. van der Meulen, J. M. Calleja, C. Tejedor, I. Prieto, D. Granados, A. G. Taboada, J. M. García, and P. A. Postigo, "Emission polarization control in semiconductor quantum dots coupled to a photonic crystal microcavity," Opt. Express 18, 13301-13308 (2010).