plasmon (rus. плазмон otherwise квант плазменных колебаний) — quasiparticle that corresponds to the quantisation of plasma oscillations, which are collective oscillations of free electron gas density.


Plasmons (electron density waves) occur in solids or near their surfaces as a result of the collective oscillation of conduction electrons about ions. Bulk plasmons copy the oscillations of conduction electrons inside a crystal’s ionic lattice. Surface plasmons, on the other hand, are quanta of free metal electron density oscillations propagating along the metal’s boundary with a dielectric. Plasmon frequency equals the frequency of plasma. Surface plasmons may couple with a photon to create quasiparticles known as polaritons.

In solids, light whose frequency is lower than the plasma frequency will be reflected, while light with frequency higher than the plasma frequency will penetrate inside the object. For most metals, the plasma frequency lies in the UV spectral region, which makes them look shiny in the visible range. Alloyed semiconductors usually have their plasma frequency in the IR spectral region.


  • Khokhlov Dmitry R.
  • Naymushina Daria A.


  1. Perlin E.Ju et al Solid State Physics. Optics of semiconductors, dielectrics and metals: A Tutorial. — SPB.: SPBGU ITMO, 2008. — 216 p.
  2. Plasmon // Wikipedia, the free Encyclopedia. — (reference date: 31.07.2010).

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