Surface Plasmon - Propagation Length and Skin Depth

Propagation Length and Skin Depth

Condensed matter physics
Phases · Phase transition
States of matter Solid · Liquid · Gas · Bose-Einstein condensate · Fermionic condensate · Fermi gas · Fermi liquid · Supersolid · Superfluid · Luttinger liquid
Phase phenomena Order parameter · Phase transition
Electronic phases Electronic band structure · Insulator · Mott insulator · Semiconductor · Semimetal · Conductor · Superconductor · Thermoelectric · Piezoelectric · Ferroelectric
Electronic phenomena Quantum Hall effect · Spin Hall effect · Kondo effect
Magnetic phases Diamagnet · Superdiamagnet
Paramagnet · Superparamagnet
Ferromagnet · Antiferromagnet
Metamagnet · Spin glass
Quasiparticles Phonon · Exciton · Plasmon
Polariton · Polaron · Magnon
Soft matter Amorphous solid · Granular matter · Liquid crystal · Polymer
Scientists Maxwell · Van der Waals · Debye · Bloch · Onsager · Mott · Peierls · Landau · Luttinger · Anderson · Bardeen · Cooper · Schrieffer · Josephson · Kohn · Kadanoff · Fisher

As an SPP propagates along the surface, it loses energy to the metal due to absorption. The intensity of the surface plasmon decays with the square of the electric field, so at a distance x, the intensity has decreased by a factor of exp. The propagation length is defined as the distance for the SPP intensity to decay by a factor of 1/e. This condition is satisfied at a length

Likewise, the electric field falls off evanescently perpendicular to the metal surface. At low frequencies, the SPP penetration depth into the metal is commonly approximated using the skin depth formula. In the dielectric, the field will fall off far more slowly. The decay lengths in the metal and dielectric medium can be expressed as

where i indicates the medium of propagation. Surface plasmons are very sensitive to slight perturbations within the skin depth and because of this, surface plasmons are often used to probe inhomogeneities of a surface.

Read more about this topic:  Surface Plasmon

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