Perets, H.B., Lahini, Y., Pozzi, F., Sorel, M., Morandotti, R. and Silberberg, Y. (2008) Realization of quantum walks with negligible decoherence in waveguide lattices. Physical Review Letters, 100(17), p. 170506. (doi: 10.1103/PhysRevLett.100.170506)