title: Geometries and materials for subwavelength surface plasmon modes.
abstract: Plasmonic waveguides can guide light along metal-dielectric interfaces with propagating wave vectors of greater magnitude than are available in free space and hence with propagating wavelengths shorter than those in vacuum. This is a necessary, rather than sufficient, condition for subwavelength confinement of the optical mode. By use of the reflection pole method, the two-dimensional modal solutions for single planar waveguides as well as adjacent waveguide systems are solved. We demonstrate that, to achieve subwavelength pitches, a metal-insulator-metal geometry is required with higher confinement factors and smaller spatial extent than conventional insulator-metal-insulator structures. The resulting trade-off between propagation and confinement for surface plasmons is discussed, and optimization by materials selection is described.
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA. zia@stanford.edu
authors.forename: Rashid
authors.initials: R
authors.lastname: Zia
authors.forename: Mark D
authors.initials: MD
authors.lastname: Selker
authors.forename: Peter B
authors.initials: PB
authors.lastname: Catrysse
authors.forename: Mark L
authors.initials: ML
authors.lastname: Brongersma
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D017097:Electric Impedance; D004867:Equipment Design / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods*; D008670:Metals / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods*
chemical_list: D008670:Metals