AVS 47th International Symposium
    Photonics Tuesday Sessions
       Session PH-TuM

Paper PH-TuM11
Plasmonics: Electromagnetic Energy Transfer and Switching Below the Diffraction Limit in Nanoparticle Chain Arrays

Tuesday, October 3, 2000, 11:40 am, Room 310

Session: Fundamental Properties and Applications of Photonic Materials
Presenter: M.L. Brongersma, California Institute of Technology
Authors: M.L. Brongersma, California Institute of Technology
S.A. Maier, California Institute of Technology
H.A. Atwater, California Institute of Technology
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The integration density of integrated optics appears to face the fundamental limitation that structures for guiding and modulation of light must have dimensions comparable to the wavelength of light. Recently however, it was theoretically shown that this problem can be circumvented by "plasmonics", i.e., transport of electromagnetic energy along linear chains of closely spaced 10-50 nm diameter metal nanoparticles. This transport relies on the coupled near-field electrodynamic interaction between metal particles that sets up coupled plasmon modes. We have modeled the electromagnetic transport properties of corners, tees, and switches that consist of chains of metal nanoparticles. Both full electromagnetic field calculations using finite difference time domain methods and calculations in the point dipole approximation indicate strong guiding of electromagnetic radiation, and electromagnetic dispersion relations are obtained. It is shown that propagation is coherent and the group velocities can exceed saturated velocities of electrons in semiconductors (about 10^5 m/s). High efficiency transmission of energy around sharp corners is possible. The transmission is a strong function of the frequency and polarization direction of the plasmon mode. The factors dictating the choices for particle and host material will be described. To date, we have also performed experiments using nanophotonic analog structures that operate in the microwave frequency regime. We find that in analogs to optical plasmonic devices operating at 8 GHz, the transmitted intensities around both sharp corners and tees are high and closely agree with the results of microwave device simulations. Finally, the operation of a "plasmon switch" that acts as an all-optical inverter is modeled. Recent efforts to fabricate and test nanoscale plasmonic structures will be discussed; we note that such "plasmonic devices" potentially are among the smallest structures with optical functionality.