# Degree of polarization for optical near fields

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**Degree of polarization for optical near fields.** / Setälä, Tero; Shevchenko, Andrej; Kaivola, Matti; Friberg, Ari.

Tutkimustuotos: Lehtiartikkeli › › vertaisarvioitu

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*Physical Review E*, Vuosikerta. 66, Nro 1, 016615, Sivut 1-7. https://doi.org/10.1103/PhysRevE.66.016615

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*Physical Review E*,

*66*(1), 1-7. [016615]. https://doi.org/10.1103/PhysRevE.66.016615

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### Bibtex - Lataa

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TY - JOUR

T1 - Degree of polarization for optical near fields

AU - Setälä, Tero

AU - Shevchenko, Andrej

AU - Kaivola, Matti

AU - Friberg, Ari

PY - 2002/7

Y1 - 2002/7

N2 - We investigate an extension to the concept of degree of polarization that applies to arbitrary electromagnetic fields, i.e., fields whose wave fronts are not necessarily planar. The approach makes use of generalized spectral Stokes parameters that appear as coefficients, when the full 3×3 spectral coherence matrix is expanded in terms of the Gell-Mann matrices. By defining the degree of polarization in terms of these parameters in a manner analogous to the conventional planar-field case, we are led to a formula that consists of scalar invariants of the spectral coherence matrix only. We show that attractive physical insight is gained by expressing the three-dimensional degree of polarization explicitly with the help of the correlations between the three orthogonal spectral components of the electric field. Furthermore, we discuss the fundamental differences in characterizing the polarization state of a field by employing either the two- or the three-dimensional coherence-matrix formalism. The extension of the concept of the degree of polarization to include electromagnetic fields having structures of arbitrary form is expected to be particularly useful, for example, in near-field optics.

AB - We investigate an extension to the concept of degree of polarization that applies to arbitrary electromagnetic fields, i.e., fields whose wave fronts are not necessarily planar. The approach makes use of generalized spectral Stokes parameters that appear as coefficients, when the full 3×3 spectral coherence matrix is expanded in terms of the Gell-Mann matrices. By defining the degree of polarization in terms of these parameters in a manner analogous to the conventional planar-field case, we are led to a formula that consists of scalar invariants of the spectral coherence matrix only. We show that attractive physical insight is gained by expressing the three-dimensional degree of polarization explicitly with the help of the correlations between the three orthogonal spectral components of the electric field. Furthermore, we discuss the fundamental differences in characterizing the polarization state of a field by employing either the two- or the three-dimensional coherence-matrix formalism. The extension of the concept of the degree of polarization to include electromagnetic fields having structures of arbitrary form is expected to be particularly useful, for example, in near-field optics.

KW - degree of polarization

KW - optical near fields

KW - degree of polarization

KW - optical near fields

KW - degree of polarization

KW - optical near fields

U2 - 10.1103/PhysRevE.66.016615

DO - 10.1103/PhysRevE.66.016615

M3 - Article

VL - 66

SP - 1

EP - 7

JO - Physical Review E

JF - Physical Review E

SN - 2470-0045

IS - 1

M1 - 016615

ER -

ID: 3361067