Introduction to Optics
Including the tools and methods currently used by researchers and engineers, this book covers the essential concepts of comprehension and reports the great progress of the current knowledge in optics.
TABLE OF CONTENTS Introduction to Optics
Annex 8.A: Electric Dipole Radiation
Any piece of material is in fact a collection of electric dipoles that can freely oscillate or that are forced to oscillate by an incoming electromagnetic wave. The purpose of this annex is to calculate the electromagnetic field radiated from an oscillating dipole.
8.A.1 Definition of an Oscillating Dipole
We refer to Figure 8.A.1 and consider a dipole made of two electric charges, + q and ? q, disposed at points Q + and Q ? separated by a distance d; by definition, the electric dipolar momentum p of the dipole is the product of the absolute value of the charges by the vector a = Q-Q +,
Figure 8.A.1: Oscillating dipole. ( r 1, ? 1, ? 1) is a unitary direct tetrahedron; r 1, is parallel to a, ? 1 is in the plane ( OP, a), ? 1 is orthogonal to the two other vectors.
If p is a constant vector, the dipole is said to be static; an oscillating dipole corresponds to the case where the distance follows a sine time variation:
8.A.2 Electric and Magnetic Fields Created by a Dipole
We will first successively consider the case of a static dipole and then of an oscillating dipole.
8.A.2.1 Static Dipole
The determination of the electric field created by a static dipole is a trivial electrostatic calculation: the field at point P in Figure 8.A.1 is parallel...
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