Total internal reflexion --- an old topic offers new surprises

by Gerd Leuchs (Erlangen)

Tuesday 17 May 2016, 11:00 → 12:00 Europe/Stockholm

C5:1007

When the electric field vectors in a light beam spiral then this is associated with angular momentum, classified as spin. In this case the angular momentum vector is usually oriented along the direction of propagation. Hence one might call this angular momentum longitudinal with the corresponding electric field spinning in the transverse plane. But this is not the only type of angular momentum that light may have. The angular momentum vector of the light beam as a whole may also lie in the transverse plane corresponding to an electric field vector spinning in a plane containing the direction of propagation. Such a situation can be found e.g. for total internal reflexion [2]. In the context of light matter interaction such a transverse spin angular momentum (t-SAM) allows for pointing the light emitted by a single sub wavelength dipole in one particular direction. The direction of emission being determined by the orientation of the t-SAM allows for constructing a nano beacon [3]. This effect may be relevant for integrated optical circuitry as well as for quantum communication networks [4].