Polarization Optimized Systems

Light exhibits a polarization degree of freedom which is of utmost importance for many applications in optics, biology and other fields. In general, the polarization defines the plane of oscillation of the electric field vector, which can vary in space and time. Especially when light beams are tightly focused or strongly confined by any means (see figure), the polarization in the focal plane can change drastically. Hence, it is necessary to take the polarization state into account when describing such a focused beam. In this context, the polarization state of a light beam can be tailored towards a certain application or system to be excited by this beam allowing for detailed studies of the system’s optical properties. Using this technique of polarization optimization or tailoring, single nano-­structures or even single atoms or ions can be investigated.

A polarized light beam is focused tightly by means of a lens or lens system. If the incoming beam is radially polarized (the electric field vectors oscillate along the radial direction of the beam; here indicated as black arrows), a strong electric field component oscillating along the propagation direction of the incoming beam is formed in the focal plane. (picture by: Peter Banzer)