Geometries and materials for subwavelength surface plasmon modes.
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.
Zia
Rashid
R
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA. zia@stanford.edu
Selker
Mark D
MD
Catrysse
Peter B
PB
Brongersma
Mark L
ML
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*
D008670:Metals