Redistribution of energy flow in a material due to damping

Li, Xin; Pierce, Donna M.; Arnoldus, Henk F.

doi:10.1364/ol.36.000349

Cited by 7 publications

(9 citation statements)

References 3 publications

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“…Energy flowing along field lines that end at the z axis does not contribute to the radiated power. Similar behavior was found for an electric dipole [4], where the bending of the field lines resulted from the imaginary part of the permittivity. Figure 3 shows a larger view of the same graph as in Fig.…”

Section: Linear Dipolesupporting

confidence: 74%

Propagation of magnetic dipole radiation through a medium

Arnoldus

2016

J. Opt. Soc. Am. A

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An oscillating magnetic dipole moment emits radiation. We assume that the dipole is embedded in a medium with relative permittivity ϵ and relative permeability μ, and we have studied the effects of the surrounding material on the flow lines of the emitted energy. For a linear dipole moment in free space the flow lines of energy are straight lines, coming out of the dipole. When located in a medium, these field lines curve toward the dipole axis, due to the imaginary part of μ. Some field lines end on the dipole axis, giving a nonradiating contribution to the energy flow. For a rotating dipole moment in free space, each field line of energy flow lies on a cone around the axis perpendicular to the plane of rotation of the dipole moment. The field line pattern is an optical vortex. When embedded in a material, the cone shape of the vortex becomes a funnel shape, and the windings are much less dense than for the pattern in free space. This is again due to the imaginary part of μ. When the real part of μ is negative, the field lines of the vortex swirl around the dipole axis opposite to the rotation direction of the dipole moment. For a near-single-negative medium, the spatial extent of the vortex becomes huge. We compare the results for the magnetic dipole to the case of an embedded electric dipole.

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Section: Linear Dipolesupporting

confidence: 74%

Propagation of magnetic dipole radiation through a medium

Arnoldus

2016

J. Opt. Soc. Am. A

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“…Figure 6 depicts the resulting field line pattern. A more detailed analysis [13] shows that near the z axis, the field lines approach the z axis under 90 • , and stop there. Therefore the z axis is a singular line of the flow pattern.…”

Section: Linear Dipole In a Mediummentioning

confidence: 99%

Propagation of Electric Dipole Radiation through a Medium

Arnoldus

2012

ISRN Optics

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When electromagnetic energy propagates through a material medium, the paths of energy flow may be altered, as compared to propagation in free space. We consider radiation emitted by an electric dipole, embedded in a medium with permittivity ε r and permeability μ r . For a linear dipole in free space, the field lines of energy flow are straight, but when the imaginary part of ε r is finite, the field lines in the material become curves in the near field of the dipole. Therefore, the energy flow is redistributed due to the damping in the material. For a circular dipole in free space, the field lines of energy flow wind around the axis perpendicular to the plane of rotation of the dipole moment. When ε r has an imaginary part, this flow pattern is altered drastically. Furthermore, when the real part of ε r is negative, the direction of rotation of the flow lines reverses. In that case, the energy in the field rotates opposite to the direction of rotation of the dipole moment. It is indicated that in metamaterials with a negative index of refraction this may lead to an observable effect in the far field.

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“…The field line ends at the z axis. A more careful analysis (Li et al, 2011a) shows that all field lines start off horizontally, so along the xy plane. Therefore, all energy is initially emitted along the xy plane.…”

Section: Linear Dipole In a Mediummentioning

confidence: 99%