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The post-fabrication control of evanescent tunnelling in photonic crystal molecules is demonstrated through the combination of selective infiltration and oxidation. By laser non thermal oxidation, we reduce the photonic coupling by more than 30% while by means of water micro-infiltration, we increase it by 28%. Fine-tuning of the photonic coupling is achieved by low-power laser oxidation and forced evaporation, opening the route to post-fabrication control of array of coupled cavities. [ABSTRACT FROM AUTHOR]

We employ a far-field analysis of the angular emission pattern to experimentally assess the symmetry of localized modes in coupled photonic-crystal cavities. We demonstrate that the spatial distribution of localized modes in photonic-crystal nanocavities may change from a bonding to an antibonding orbital, a feature that is unusual in quantum mechanical coupled systems. Experimental data are confirmed by numerical calculations and interpreted in terms of the peculiar oscillatory behavior of the evanescent waves in photonic-crystal band gaps. [ABSTRACT FROM AUTHOR]

Abstract: We report on a set of experimental measurements aimed to fully characterize both the spatial and angular pattern of the optical modes of photonic crystal microcavities. By using a confocal microscope we resolve the spatial distribution of the mode on the sample surface. With the same setup, by introducing an iris placed on a translational stage within the collimated beam region of the confocal microscope, we are able to measure the far field angular pattern of the microcavity modes. The experimental data are compared with theoretical predictions obtained by finite difference in time domain calculations and a very good agreement is found. [Copyright &y& Elsevier]

Abstract: We directly investigate, by means of near-field spectroscopy, the spatial distribution of the optical cavity modes of 2D photonic crystal microcavities. Numerical simulations confirm that the photoluminescence maps of quantum dots embedded in the photonic structure qualitatively match the spatial modulation of the electric field intensity. [Copyright &y& Elsevier]