Morphology and plasmonic properties of self-organized arrays of ...

10 CHAPTER 1. THEORYEλBkFigure 1.1: Schematic representation of a plane monochromatic EM wave, linearly polarized,propagating along the direction defined by its wave vector k. The electric E andmagnetic B fields are in the vertical and horizontal planes, respectively.the beam is said unpolarized. In contrast, when the state of oscillation of the EM fields,called polarization, is the same for all the components of the beam, light is said polarized.For a EM plane wave, three possible states of polarization can be defined, linear, circularand elliptical. For linear polarized light (fig. 1.2(a)) the orientation of the electric fieldsis constant along a specific direction, so that, as the wave propagates, they oscillate ina fixed plane called polarization plane. Instead, when light is elliptically (fig. 1.2(b))or circularly (fig. 1.2(c)) polarized the electric field vector viewed along the propagationdirection describes an ellipse (or a circle) around its wave vector k. The rotation is definedright-handed or left-handed when the observer sees the fields rotate counter-clockwise orclockwise, respectively.polarization planea. b. c.Figure 1.2: Diagram of different states of polarization of light, and corresponding pathstraced by the tip of the electric field vector (red lines). Panel a: linear polarization, Eoscillates along a constant direction. Panel b: elliptical polarization, E traces an ellipsein each plane perpendicular the direction of propagation. Panel c: circular polarization,special case of elliptical polarization where E traces a circle.