I.  Liberal and Engheta, N., ?Multiqubit subradiant states in N-port waveguide devices: $\varepsilon$-and-$?$-near-zero hubs and nonreciprocal circulators?, Physical Review A, vol. 97, p. 022309, 2018.

I.  Liberal and Engheta, N., ?Near-zero refractive index photonics?, Nature Photonics, vol. 11, p. 149, 2017.

I.  Liberal, Mahmoud, A. M., Li, Y., Edwards, B., and Engheta, N., ?Photonic doping of epsilon-near-zero media?, Science, vol. 355, pp. 1058?1062, 2017.

I.  Liberal and Engheta, N., ?Zero-index structures as an alternative platform for quantum optics?, Proceedings of the National Academy of Sciences, vol. 114, no. 5, pp. 822 - 827, 2017.