As nanonphotonics and nanoelectronics are pushed down towards the
molecular scale, interesting effects emerge. We discuss how
birefringence (different propagation of two polarizations) is
manifested and could be useful in the future for two systems:
coherent plasmonic transport of near-field light and
spin-birefringence.
We first show that a very simple dipole-coupling model, valid for
coherent transport on small scales, predicts that the different
polarizations of near-field light can travel in opposite directions,
i.e., with one of them having a negative refraction index. More
importantly, at special velocities a "conical intersection"-like
phenomena occurs, with very easy scattering from one polarization to
the other. Therefore, the light direction could be changed abruptly,
leading hopefully to interesting future devices
The second part of the talk discusses simulations of control of
spin-current on the molecular scale without using magnetic fields.
Spin-orbit effects coupled with a circular geometry make an electron
with spin up capture a different phase then an electron with spin
down; a simulation of a transport through
(acetylene-bitellurium-naphthalene)9 shows that this effect can be
used to flip the spin of an initially polarized electron, and the
flipping is controlled by the injection energy of the electron.
Researchers should cite this work as follows: