Polarization entanglement of surface plasmons?

Dr. M. van Exter, Leiden University

Quantum entanglement is one of the most fascinating aspects of quantum
mechanics and the essential ingredient of quantum computers. After a brief
introduction on quantum information, we discuss how polarization-entangled
photon pairs are naturally generated in nonlinear optical process and how they
can be used in more sophisticated experiments. As a first experimental
ingredient we show how the quantum nature of these entangled pairs allows for
a violations of the classical Bell inequality by what Einstein called "spooky
action at a distance". As a second experimental ingredient we show that metal
films perforated with arrays of holes can have a surprisingly large
transmission at certain optical frequencies, due to the resonant excitation of
surface plasmons. A combination of these concepts brings us to the crucial
experiment, where metal hole arrays are illuminated with
polarization-entangled photons and where we wonder if and under which
conditions the (generally fragile) entanglement survives the conversion from
photon to surface plasmon and back.