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M. C. Rechtsman, J. M. Zeuner, Y. Plotnik, Y. Lumer, D. Podolsky, F. Dreisow, S. Nolte, M. Segev and A. Szameit
Nature 496, 196-200 (2013)

Topological insulators are a new phase of matter with the striking property that conduction of electrons only
occurs on the surface, and are currently one of the most exciting fields of condensed matter research. They
are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. An
interesting open question has been whether it is possible to make a topological insulator for light, a question
which has been answered by the paper of Rechtsman and colleagues.

In their paper they demonstrate the first experimental realisation of a photonic topological insulator,
comprised of optical photons and without the need for an external magnetic field - using a method which is
both simply and practical. Their experiments directly demonstrate the existence of an electromagnetic wave
which can bypass obstacles and imperfections, exactly as predicted by the theory of topological insulators,
results which suggest many possible applications of their scheme.