Semi-infinite chain of small nanoparticles

RAÚL A. BUSTOS MARÚN; EDUARDO A. CORONADO; HORACIO M. PASTASWKI

La Falda, Córdoba, Argentina

Workshop; Mini-School on Disordred Systems 2008 and 6th International Workshop on Disordered Systems; 2008

We are interested in the interaction of light with arrays of plasmonic particles. In particular we are focused in phenomenas like Raman enhancement induced by nanoparticles aggregates, defects and localization of the plasmon polariton in nanoparticles chains, and the injection of excitation into the chain. As a first step of these studies we analyzed the local density of photonic state (LDPS) of the first site of a semi-infinte chain varying the distance r between the first nanoparticle and the rest of the chain. We describe the system as a liner chain of coupled dipoles within the quasielectrostic approximation (applicable to small nanoparticles arrays) [1-3]. We found that the LDPS presents a great dependency with r evolving from a monomer-like spectra at long distances to a localized state at short distances (compatible with a dimer-like spectra) passing through resonant and virtual states at intermediate distances. We also found that taking a weak-damping limit provides a very useful and intuitive picture of the system. This approximation allow us to obtain analytical expressions for the local density of photonic state and the exact conditions for the phase transitions between the different regimes. [1] Roi Baer, Kenneth Lopata, and D. Neuhauser, J. Chem. Phys. 126, 014705 (2007). [2] J. V. Hernandez, L. D. Noordam, and F. Robicheaux, J. Phys. Chem. B 108, 15808 (2005). [3] M. L. Brongersma, J. W. Hartman, and H. A. Atwater, Phys. Rev. B. 62, R16356 (2000).